TA 439 
.C7 
Copy 1 



IOWA STATE COLLEGE 
AGRICULTURE AND MECHANIC ARTS 
OFFICIAL PUBLICATION 



Vol. XIX 



MAY 18, 1921 



No. 51 



METHOD OF PROPORTIONING CONCRETE MATERIALS 
SCREENED AND UNSCREENED GRAVEL 



BY 
R. W. CRUM 




BULLETIN 60 



ENGINEERING EXPERIMENT STATION 
AMES, IOWA 



Published weekly by Iowa State College of Agriculture and Mechanic Arts, Ames, Iowa. 
Entered as second-class matter, and accepted for mailing at special rate of postage 
provided for in Section 429, P. L. & R., Act August 24, 1912, authorized April 12, 1920 



iti Olograph 



PURPOSE OF .THE STATION 

The purpose of the Engineering Experi- 
ment Station is to afford a service, through 
scientific investigations, evolution of new 
devices and methods, and tests and analyses 
of materials : 

For the manufacturing and other engineer- 
ing population and industries of Iowa; 

For the industries related to agriculture, 
in the solution of their engineering problems; 

For all people of the State in the solution 
of the engineering problems of urban and 
rural life. 



IOWA STATE COLLEGE 

OF AGRICULTURE AND MECHANIC ARTS 

OFFICIAL PUBLICATION 



Vol. XIX 



MAY 18, 1921 



No. 51 



METHOD OF PROPORTIONING CONCRETE MATERIALS 
SCREENED AND UNSCREENED GRAVEL 



BY 
R. W. CRUM 

Engineer of Materials and Tests 

IOWA HIGHWAY COMMISSION 

Formerly Structural Engineer 

ENGINEERING EXPERIMENT STATION 




BULLETIN 60 



ENGINEERING EXPERIMENT STATION 
AMES, IOWA 



Published weekly by Iowa State College of Agriculture and Mechanic Arts, Ames, 
Iowa. Entered as second-class matter, and accepted for mailing at special rate of 
postage provided for in Section 429, P. L. & R., Act August 24, 1912 authorized April 
12, 1920. 



STATE BOARD OF EDUCATION ~ n 

Members V_y 
Hon. D. D. Murphy, President ' Elkader 

Hon. George T. Baker Davenport 

Hon. Chas. R. Brenton Dallas Center 

Hon. P. K. Holbrook Onawa 

Hon. Edw. P Schoentgen Council Bluffs 

Hon. Frank F. Jones Villisca 

Hon. Paul Stillman J eft" erson 

Hon. W. C. Stuckslager Lisbon 

Miss Anna B. Lawther Dubuque 

Finance Committee 
Hon. W. E. Boyd, President Cedar Rapids 

Hon. Thomas Lambert Sabula 

Hon. W. H. Gemmill, Secretary Des Moines 

ENGINEERING EXPERIMENT STATION 
Station Council 

(Appointed by the State Board of Education) 

Raymond A. Pearson, LL. D : President 

Anson Marston, C. E Professor 

Louis Bevier Spinney, B. M. E Professor 

Warren H. Meeker, M. E Professor 

Fred Alan Fish, M. E. E. E Professor 

Allen Holmes Kimball, M. S Professor 

O. R. Sweeney, M. S., Ph. D Professor 

Fred R. White, B. C. E Chief Engineer, Iowa Highway Commission 

Station Staff 
Raymond A. Pearson, LL. D President Ex-officio 

Anson Marston, C. E Director and Civil Engineer 

Warren H. Meeker, M. E Mechanical Engineer 

Fred Allan Fish, M. E. E. E Electrical Engineer 

Allen Holmes Kimball,, M. S Architectural Engineer 

O. R. Sweeney, M. S., Ph. D Chemical Engineer 

Charles S. Nichols, C. E Sanitary Engineer 

Louis Bevier Spinney, B. M. E Illuminating Engineer and Physicist 

William J. Schlick, C. E Drainage Engineer 

T. R. Agg, C. E Highway Engineer 

John Edwin Brindley, A. M., Ph. D Engineering Economist 

Max Levine, S. B , Bacteriologist 

S. L. Galpin, Ph. D Geologist 

J. H. Griffith, M. S Structural Materials Engineer 

Paul E. Cox, B. S. in Cer. Eng Ceramic Engineer 

A. K. Friedrich, E. M Mining Engineer 

G. W. Burke, B. S. in Chem. Eng Chemist 

Carl H. Giester, B. S Assistant Chemist 

Clyde Mason, B. S. in E. E., C. E Assistant Engineer 

Geo. W. Rogers Mechanician 

H. E. Pride, B. S. in C. E Bulletin Editor 



LIBRARY OF CONGRESS 
«*ecsivie 

MAY 5 192^ 

OOCUMiliiTJS .->/». -JION 



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ACKNOWLEDGMENTS 

The laboratory investigations upon which the 
method of proportioning is based were carried 
out by P. J. Preston. The laboratory tests made 
in verification of the method were made by P. J. 
Preston and Clyde Mason. 

The experimental work done in connection 
with the work of the Iowa Highway Commission, 
which also verifies the method was under the 
direction of P. J. Preston, Assistant Engineer 
of Materials, assisted by Mark Morris. 

Various standard works have been consulted 
in preparing the bulletin, notably "Concrete, 
Plain and Reinforced," by Taylor and Thomp- 
son, and Johnson 's ' ' Materials of Construction. ' ' 



METHOD OF PROPORTIONING CONCRETE MATERIALS- 
SCREENED AND UNSCREENED GRAVEL 

INTRODUCTION 

Thru rears of practice it has become customary to specify for concrete 
mixtures, proportions containing approximately twice as much coarse 
aggregate as sand, and experience has demonstrated that satisfactory 
concrete can be thus produced. However, investigation of the material 
resources of Iowa discloses the fact that a large part of the state 
must depend upon gravel for concrete aggregates, and that the deposits 
of gravel invariably contain considerably more sand than coarse pebbles. 
It would seem therefore, that in order to use Iowa materials to the best 
advantage, engineers should develope proper methods for making con- 
crete from mixtures containing more of the finer material than has here- 
tofore been customary. 

The investigations reported in this bulletin were planned and executed 
for the purpose of developing proper methods for the use of Iowa gravel 
containing an excess of sand. Such a method was derived from a study 
of the data and is presented in this bulletin. The method has been 
corroborated by other laboratories and has been applied in practice 
on a large scale with satisfactory results. In so far as to whether or 
not the sand and coarse pebbles are separated by screening and remixing, 
or used as pit-run gravel is immaterial with respect to the theory involved. 
Pit-run gravel is, of course, variable in composition and if it is used 
the proportion of cement will need to be changed frequently. This is 
not an insuperable obstacle to its use. It is often merely a matter of 
adequate inspection. There are two cases in which the use of pit-run 
gravel is feasible and logical. 

(a) Small jobs in which the amount of material involved is small. In 
this case uniform mixtures can be secured by a reasonable expenditure of 
effort There is an immense amount of work every year in this class. 

(b) Large jobs upon which stock piles containing more than 1000 
cubic yards can be accumulated. Handling the gravel from and to such 
stock piles tends to unify the mass. 

In either case constant inspection and change in proportions when 
needed is essential to satisfactory results. However, the details of inspec- 
tion are simple and can be performed with little training or effort. 

In comparing screened and unscreened material it should be borne in 
mind that the advantage in screening is lost unless the dividing line be- 
tween fine and coarse aggregate is accurately defined and maintained 
within narrow limits. 



I. SYNOPSIS OF THE PROCESS OF MAKING CONCRETE 

The making of concrete is essentially a manufacturing process, but 
it suffers under the handicap of having no fixed plant location since the 
concrete must usually be made at the site of the structure. It is further- 
more a chemical as well as a mechanical process, and is subject to 
various disturbing influences on that account. 

The factor that has had the most to do with the growth of the concrete 
industry and also with its slowness of scientific development has been 
the fact that anyone could take some cement, water, sand and stone, 
mix them together and get a substance that would set and harden. The 
job was so easy, it took a long time to establish the fact that most con- 
crete so made was a very inferior article. That so much successful 
concrete work has been done in spite of poor methods is evidence of the 
value of the material. The basic requirements for the manufacture 
of concrete are today well established, and failure to make at least 
sound concrete is inexcusable. 

The factors upon which the quality of concrete depends are : 

1. The raw materials. 

2. The mixture or proportions of the materials. 

3. The manufacturing operation or fabrication. 

It is necessary that materials be selected not only for general quality 
but for their suitability for the class of concrete contemplated. Material 
good in quality and suitable for heavy mass concrete might be entirely 
unsuited for the construction of concrete pavement. 

For successul work the raw materials must be properly proportioned. 
By varying the amounts of the various materials it is possible to make 
concretes of a wide range of strength. It should always be made as 
strong as the conditions require, but additional strength is not nec- 
essary. When concrete of low strength is permissible, it is not 
good practice to allow the use of inferior materials. Good mater- 
ials should be used and the saving made by using less cement. 

The actual operations in making concrete consist in measuring, 
mixing, placing, and curing the product and it is needless to say that 
it is vitally important that these operations be correctly performed. 
Good materials properly proportioned, are often ruined in the handling, 
and, the best manufacturing conditions will not make up for poor 
material or wrong mixtures. 

MATERIALS 

Cement. The cement is now the most reliable article entering into 
concrete. The established brands are uniform and reliable and regularly 
pass the "standard specifications." Such an excellence of product is 
only secured and maintained by constant vigilance on the part of the 
plant chemist, and it is not outside the realm of possibility even today 
that a system may at times fall down in some detail, and an inferior 
batch of cement result. Cement testing is not a costly process, and it 



J 

gives a proper insurance to both the maker and the consumer. All 
eenient should be tested when received. On all work of any importance 
it should be specified that "the cement to be used shall meet the require- 
ments of the standard specifications for Portland cement of the American 
Society for Testing Materials." 

Water. The water used in mixing should be free from oil, alkali 
or organic matter. 

Aggregates. The aggregate, or total inert material used with water 
and cement to make concrete, is usually divided into fine aggregate 
and coarse aggregate. 

A generalization as to recommendations for concrete aggregates as 
made by the * Joint Committee on Concrete is as follows : 

"Fine Aggregate shall consist of sand, stone screenings or other 
inert materials with similar characteristics, or of a combination thereof, 
having clean, hard, strong, durable, uncoated grains and free from in- 
jurious amounts of dust, lumps, soft or flaky particles, shale, alkali, 
organic matter, loam or other deleterious substances. 

"Fine aggregate shall range in size from fine to coarse, preferably 
within the following limits : 

Passing thru No. 4 sieve not less than 95 percent 

Passing thru No. 50 sieve not more than 30 percent 

Weight removed by decantation not more than 3 percent 

"Fine aggregate shall preferably be of such a quality that mortar 
briquettes, cylinders or prisms, consisting of one part by weight of 
Portland cement and three parts by weight of fine aggregate, mixed 
and tested in accordance with the methods described in the Standard 
Specifications and Tests for Portland Cement will show a tensile or 
compressive strength at ages of 7 and 28 days not less than that of 1 :3 
standard Ottawa sand mortar of the same plasticity made, with the same 
cement. However, fine aggregate which fails to meet this requirement 
may be used, provided the proportions of cement, fine aggregate, coarse 
aggregate and water are such as to produce concrete of the strength 
specified. In testing aggregate, care should be exercised to avoid the 
removal of any coating on the grains which may effect the strength. 
Natural sand should not be dried before being made into mortar, but 
should test stronger in tension in the 1 :3 proportion than Ottawa sand. 
be determined on a separate sample and the weight of the sand used 
in the test corrected for the moisture content." 

Since the Ottaw r a sand is not a dense mixture, first class natural sand 
should test stronger intension in the 1 :3 proportion than Ottawa sand. 

The strength test is not an absolute criterion of the concrete making- 
quality of sand. Its value is rather comparative. It has been shown by 
Professor Duff A. Abrams that sands of low mortar strength are often 

* Joint Committee on Concrete and Reinforced Concrete. American Society Civil Engineers, 
American Society for Testing Materials, American Railway Engineers Association, Portland Ce- 
ment Association and American Concrete Institute, June 4, 1921. 



8 

suitable for use in concrete when mixed with the proper amount of 
coarse aggregate and cement. In general, a low strength test is due, 
either to injurious impurities or to poor grading of the particles. In 
the first case it should not be used. In the second case it may often 
be used if the concrete mixture is properly proportioned. On the other 
hand, sands giving a high mortar strength are often unsuitable for some 
particular use on account of the presence of soft particles of stone, shale, 
iron oxide, and similar substances. 

The significant factors with respect to the quality of sand for use in 
concrete are as follows : 

(1) Character and texture of grains. 

(2) Amount and kinds of impurities present. 

a. Finely divided clay. 

b. Lumps of clay. 

c. Coating on sand grains. 

d. Organic silt. 

(3) Size of particles. 

The grains of sand should preferably be of siliceous material, partic- 
ularly for use in a wearing surface. 

Particles of mica, iron oxide, and shale are not hard and durable. Mica 
is usually classed as an injurious impurity. Shale particles are very 
injurious in that hydration tends to make them expand and rupture the 
concrete, especially when near the surface. 

Some sands resulting from the decomposition of sand stones are not 
durable. Their quality depends upon the cementing material of the 
original stone, since a high percentage of the sand grains themselves 
are composed of yet smaller grains cemented together. The cementing 
materials in the order of durability are as follows: silica, calcium car- 
bonate, iron oxide, and clay. The latter, especially, does not provide a 
very durable sand for the manufacture of concrete. 

A microscopic examination will give one familiar with such work a 
good idea of the quality of sand grains. Limestone can be detected by 
treating the sand with a weak solution of hydrochloric acid. If lime is 
present it will, effervesce. The best method of determining the value of 
sand is by actual strength tests of the mortar made from the material, 
except that other determinations must be made of the wearing value, and 
all other factors must be taken into account. 

Impurities. In general the only safe procedure to follow in writing 
specifications for sand is to specify clean material, although the effect 
of the impurities may or may not be injurious, depending on the char- 
acter of the silt and the amount of cement in the mixture. 

The effect of finely divided clay or other chemically inert substances 
is to increase the strength of lean mixtures and to decrease the strength 
of rich mixtures. The action is purely mechanical and is due to the void 
filling properties of the clay. For a dense mixture a certain amount of 
fine material is necessary, and considering density only it is immaterial 



9 

what this fine material is, if it is not chemically injurious. Therefore, 
finely divided clay in lean mixtures in which there is not enough cement 
to satisfy the mechanical condition of maximum density will be a benefit. 
On the other hand, in rich mixtures in which there is cement enough 
for the density consideration, clay would be detrimental. 

The difficulty with allowing the use of material containing clay is the 
uncertainty as to its real quality. Without laboratory facilities and 
very frequent analyses, it is not safe to use such material. The certainty 
of high quality and uniformity of product resulting from the use of 
clean material will more than compensate for the extra amount of cement 
occasionally needed to make a dense mixture. Lumps of clay or shale 
in any appreciable amount, render a sand or gravel unfit for use in 
concrete. A coating of clay or other impurities upon the sand or stone 
particles prevents adhesion between the cement and aggregates. Or- 
ganic silt in very small amounts may interfere with the chemical action 
and cause ultimate disintegration of the concrete. 

It will be seen from this discussion that knowledge of the total amount 
of impurities is insufficient in judging of the effect of the impurities 
upon the quality of the sand or gravel. The best, and in the end, the 
cheapest method of testing for this effect is to make the strength test 
on the material, as recommended in the quotation from the report of the 
Joint Committee. This will, of course, tell whether the sand is fit for 
use or not. 

In the event that the strength test is not satisfactory, it becomes 
desirable to ascertain the reason. The presence of limestone, shale, 
clay or other soft particles may be detected with the aid of a microscope. 
Treating the sand with a dilute solution of hydrochloric or muriatic 
acid will cause limestone particles to effervesce. Treating the sand 
with a 3 percent solution of sodium hydroxide will detect the presence 
of organic matter. If organic matter is present, it will form a reddish 
colored solution with the sodium hydroxide. If no organic matter is 
present the liquid will be colorless or light yellow. Dangerous amounts 
of organic matter are shown by dark colored solutions ranging from 
dark red to black. 

The effect of the size of particles or grading of aggregate is more a 
matter of proportioning cement to aggregate than of determining suit- 
ability for use. It is possible, with aggregates graded in size from the 
finest to the coarsest particles, according to recognized standards, to 
make a much stronger and more impermeable concrete than with aggre- 
gate not so graded. 

"Coarse aggregate* shall consist of crushed stone, gravel, or other 
approved inert materials with similar characteristics, or combinations 
thereof, having clean, hard, strong, durable, uncoated particles free 
from injurious amounts of soft, friable, thin, elongated or laminated 
pieces, alkali, organic or other deleterious matter." 

* Joint Committee on Concrete recommendations. 



10 

The quality of coarse aggregate depends upon the same factors as 
does the fine aggregate, namely . character and texture of particles. 
amount and character of impurities, and grading of particles. The 
quality: of coarse aggregate may be better inspected by a visual exami- 
nation than that of the fine material. The quality of the stone is usually 
apparent to an inspector familiar with the different rocks (and no other 
should attempt to judge such material) and the presence of much 
dirt is also easily detected. The coarse aggregate is best when uniformly 
graded in size from the finest to the coarsest particles. A sieve analysis 
is usually necessary to decide the quality from this standpoint. In 
gravels the principal defects are usually shale pebbles, soft particles, 
and masses of finer grains loosely cemented together. In crushed stone, 
the defects are usually excessive crusher dust, flat or elongated par- 
ticles and foreign material such as clay, shale or dirt. The stones which 
crush into cubical fragments are to be preferred to those which crush 
into flakes. 

The following extracts from the Specifications for Concrete Road 
Construction of the Iowa Highway Commission, illustrate requirements 
for high class material. 

Fine aggregate shall be a natural sand consisting of particles of durable rock. 
It shall be clean within the limits herein prescribed and free from particles of 
mica, shale, disintegrated granite and other deleterious substances. It shall be 
considered to be free from organic impurities if the solution, formed by treating 
the sand with a diluted solution of sodium hydroxide (XaOH) according to the 
method herein prescribed, is colorless, or is of a light yellowish color. 

"Fill a twelve (12) ounce graduated prescription bottle to the four and one-half 
(4%) ounce mark with the sand to be tested. Add a three (3) percent solution 
of sodium hydroxide until the volume of sand and solution after shaking amounts 
to seven (7) ounces. Shake thoroughly and let stand for twenty-four (21) hours. 
Observe the color of the clear liquid above the sand. ' ' 

The fine aggregate shall be reasonably well graded from coarse to fine, and not 
to exceed five (5) percent shall be retained on the sieve having .185 inch square 
openings. Not to exceed five (5) percent shall pass the one-hundred-mesh sieve. 

It shall contain not more than two and one-half (2 1 o) percent of clay by actual 
dry weight. 

Mortar composed of one part by weight of Portland cement and three parts by 
weight of sand, mixed and tested in accordance with the methods referred to in 
II. S. Bureau of Standards, Circular Xo. 33, shall have a tensible strength at the 
age of 7 and 28 days of not less than one hundred (100) percent of that developed 
by mortar of the same proportions and consistency made of the same cement and 
standard Ottawa sand. 

The coarse aggregate for Type A (one course) concrete pavement shall conform 
to the requirements for one of the three following classes: 

CLASS OXE . Class one coarse aggregate shall consist of clean, sound, crushed 
trap rock, quartzite or granite. This class of aggregate shall not contain more 
than fifteen (15) percent of limestone, sandstone or other similar soft material. 
Such limestone, sandstone or other material shall have a French coefficient of wear 
of not less than eight (8). 

CLASS TWO. Class two coarse aggregate shall consist of screened and washed 
gravel or pebbles. It may contain a quantity of material obtained from crushing 
the oversized stone found in the deposit. Any limestone, sandstone or other material 



11 

contained in this class of aggregate shall have a French coefficient of wear of not less 
than seven (7). 

CLASS THREE. Class throe coarse aggregate shall consist of material crushed 
from clean, sound limestone having an average French coefficient of wear of not less 
than seven (7). It shall be of fairly uniform quality and shall not contain more than 
five (5) percent of material having a French coefficient of wear as low as five (5). 
Stone shall be considered to have met this specification if the average of the 
tests made shows a French coefficient of seven (7) or more and no individual 
tests show a French coefficient of less than six (6). 

In any of the three classes of coarse aggregate the soft or partially disintegrated 
particles shall not exceed two and one-half (2 1 /)) percent. The coarse aggregate 
shall contain no slate, coal or other materials which easily disintegrate, and shall 
be free from frozen lumps, sticks, flat and elongated pebbles and vegetable or 
other deleterious matter. The coarse aggregate may contain not more than five- 
tenths (5/10) percent of shale pebbles, if in the opinion of the engineer such 
pebbles are not of an especially injurious nature. When tested by means of laboratory 
screens, the coarse aggregate shall meet the following requirements: 

Passing a screen with 2.y 2 in. openings 100% 

Passing a screen with \y 2 in. openings 70 to 100% 

Passing a screen with % in. openings 30 to 60% 

Retained on a screen with .185 in. openings 95% 

Unscreened gravel for use as conbined fine and coarse aggregates for Type A 
or Type B concrete pavement shall consist of clean, sound particles. That portion 
of the unscreened gravel passing a sieve having .185 in. square openings shall 
conform to the requirements for fine aggregate in clause D-3 (the first clause of 
this extract). That portion of the unscreened gravel retained on the .185 in. square 
opening sieve shall conform to the requirements for class two coarse aggregate. 

Coarse aggregate for Type B concrete pavement, except the wearing course of 
abrasion resisting stone, shall meet the requirement for coarse aggregate for Type 
A concrete pavement, excepting that a source of supply of crushed stone not 
meeting the requirement as to French coefficient of wear may be approved providing 
it meets the following conditions : Concrete specimens made from a representative 
sample of the probable output of the quarry, selected by a representative of the 
State Highway Commission, when mixed with cement and a well graded natural 
sand, in the proportion of 1:2:4 by weight shall develop an average crushing 
strength at the age of 28 days of 2,500 pounds per square inch. Tests will be 
made in accordance with the American Society for Testing Materials, tentative 
standard method for ' ' Making and Storing Specimens of Concrete in the Field ' ' 
No. C31-20T. 

Coarse aggregate for the wearing course of Type B concrete pavement shall con- 
sist of clean, sound crushed trap rock, quartzite, granite, or gravel pebbles. This 
aggregate shall contain not more than fifteen (15) percent of limestone, sandstone 
or other similar soft material. Such limestone, sandstone, or soft material shall 
have a French coefficient of wear of not less than eight (8). The soft or par- 
tially disintegrated particles shall not exceed two and one-half (2y 2 ) percent. It 
shall contain no slate, shale, coal or other materials which easily disintegrate, and 
shall be free from frozen lumps, sticks, flat and elongated pebbles, and vegetable or 
other deleterious matter. It shall pass, when dry, a screen having two and one-half 
(2i/;) inch openings, and not more than ten (10) percent shall pass an opening 
of one (1) inch. 

II. THEORY OF PROPORTIONING CONCRETE MIXTURES 

Fundamentally the strength of concrete must depend upon two fac- 
tors; the amount of solid material in a given volume, and the degree 
to which the solid particles are cemented together. 



12 

If with a given aggregate each particle is coated with a film of cement, 
and then the spaces between the grains filled with cement paste, a con- 
crete of maximum density would result. If some of the cement paste 
filling in the spaces could be replaced with stone particles harder than 
cement, concrete of about the same density but stronger would be ob- 
tained. Carrying this line of reasoning to a logical conclusion, eventually 
a mixture very similar to a natural sandstone or conglomerate and prob- 
ably as strong would be reached. This condition cannot be attained in 
practice, and the problem is therefore to approach it as nearly as possible 
by proportioning the available materials to the best advantages. 

It is the necessity of mixing the materials with water that makes this 
problem indeterminate of solution. If dry cement were to be used to 
fill in the spaces between the particles of aggregate, it might be possible 
to determine the volume of this void space and add thereto an equal vol- 
ume of cement by carefully sifting and shaking it into place, but it is 
not possible to so fill these voids with a paste of cement and water. 
The film formed on the surface of the grains wedges them apart and 
thus increases the void space an indeterminate amount. Hence, a deter- 
mination of the percentage of voids in an aggregate is not a criterion of 
the amount of cement needed to give a concrete of maximum strength. 

Rule for Proportioning. No exact rule can be formulated for mak- 
ing a mixture of maximum strength. However, taking into account the 
factors which effect the strength and density, a working rule can be 
formulated which will assure concrete adequate for the work it must do. 
The application of such a rule will depend largely upon experience 
and experimental research. Such a rule for proportioning concrete is 
as follows : 

Use the best graded aggregate available, with enough cement to yield 
concrete of the desired quality, and mix with the least amount of water 
which will give a workable mixture for the condition under which the 
concrete must be placed. The fundamental laws upon which this rule 
depends are these : 

1. The strength of the concrete depends upon the amount of solid ma- 
terial present in a unit volume. 

2. The strength of concrete depends upon the extent to which the 
particles of solid material are cemented together. 

The amount of solid material in a volume depends primarily upon the 
grading of the aggregate and upon the amount of water used in mixing. 
The cementing value depends upon the amount of cement and water and 
upon the surface area of the particles to be cemented together. The 
surface area is of course a function of the grading of the aggregate. To 
state the laws more simply : The quality of concrete depends upon the 
amount of cement, the amount of mixing water, and the grading of the 
aggregate. 

Water. Too much emphasis cannot be put upon the effect of the 
amount of the mixing water. The strength is vitally dependent upon the 



13 

amount of mixing water. Denser mixtures can be made from a well 
graded aggregate than from one not so well graded, because a given 
consistency can be secured with less water. No advantage accrues 
from using well graded aggregate unless advantage is taken of the fact 
that such aggregate can be mixed with less water. An excess of water 
will even cause a very rapid decrease in strength of concrete made from 
well graded material. 

The function of the water in mixing concrete is two-fold ; first it pro- 
vides moisture for the chemical reactions, second, it lubricates the mass 
so that it can be handled and placed. The water used for lubrication 
eventually evaporates leaving voids which, of course, reduce the strength. 
Other voids occur from failure to pack the material into the least possi- 
ble space. If the void space, due to evaporation can be decreased by 
using less water, and the same degree of compactness attained, the 
strength will undoubtedly be increased. It is found, however, that when 
using concrete of such dryness that tamping is necessary to secure this 
compactness, the void space due to poor packing increases as fast or 
faster than the voids are decreased by using less water. Therefore, 
a limit is reached somewhere beyond which the strength cannot be in- 
creased by using less mixing water. Hence the rule "Use as little water 
in mixing as will yield a workable mixture." The advantage of w^ell 
graded material here becomes apparent from the fact that this workable 
mixture can be secured with less water. 

What constitutes the dryest workable mixture for a given class of 
work should be decided in advance and made a part of the specifications. 
The consistency will necessarily vary for different kinds of work; a 
paving base may be made much dryer than a reinforced beam. The 
beam will need more cement to compensate for the additional water. 

Consistency Specifications. The consistency may be specified if 
some means of identification be provided, and the requirement rigidly 
enforced. Or the exact amount of water may be specified in the propor- 
tions as well as the amounts of cement and aggregate. The practical 
application of such a proportion will require the engineer in charge to 
make frequent determinations of the amount of water held in the piles 
of aggregate and correct the volumes of water and aggregate going into 
the mixture. This proceedure is entirely practicable and scientific, the 
only difficulty being that the amount of water to yield the proper con- 
sistency can seldom be determined in advance of starting operations. 
When the mixer is started the consistency can be established, the proper 
volume of water determined and subsequent control will be a simple 
matter of routine. This method, of course, does not apply if the grading 
of the aggregate is not uniform. When variable aggregates are used, 
a superintendent is needed who knows what proper consistency (dryest 
workable mixture) is and how to get it. 

A method of measuring consistency by noting the amount a cylinder 
or cone of the concrete will slump immediately after being mixed is being 



14 

extensively used. The method has given fairly satisfactory results as 
a means of controlling consistency on the job, but is lacking in exactness 
as a laboratory measure. A typical specification for consistency is as 
follows : 

There shall be used such an amount of water that the consistency of 
all the batches of concrete will be the same, the amount of water for 
each being carefully measured. The consistency shall be such that the 
concrete will require considerable tamping. There will not be tolerated 
a consistency that would tend to separate the fine particles from the 
coarse. 

* ' ' The consistency of the concrete shall be determined by the following test : 
"A truncated cone, four inches top diameter, eight inches bottom diameter, 

and twelve inches high, shall be filled with concrete in three layers, approximately 
four inches in thickness. Each layer shall be puddled by twenty-five to thirty 
strokes with a 5/8 in. round steel bar twenty-one inches long pointed at the lower 
end. The cone shall then be removed and the vertical settlement, or ' ' slump, ' ' of the 
concrete noted. The slump shall not exceed one (1) inch when a mechanical finishing 
machine is to be used and shall not exceed two (2) inches when the finishing is 
to be done by some other method permitted in the specifications. 

1 ' The proper consistency depends on the ratio of fine to coarse aggregate being 
used, and will be established by the engineer, within the limits prescribed herein. ' ' 

Well Graded Aggregate. As to what constitutes well graded ag- 
gregate, no general rule is available. The only authoritative guide 
available at present is the recommendation of the Joint Committee on 
Concrete, that fine aggregate should pass a % inch screen and not more 
than 30 percent should pass a No. 50 screen, and that coarse aggregate 
should be uniformly graded from 14 inch to the maximum size desired. 
The best relation between fine and coarse aggregate will depend some- 
what upon the service for which the concrete is intended. Where 
strength is the only requirement the volume of coarse aggregate is 
usually made twice the volume of fine aggregate, as in 1-2-4 for rein- 
forced concrete structures, but where smooth working qualities are 
important it is usually well to increase the volume of fine aggregate, as 
in 1-2-3 for concrete pavement. It will be demonstrated in this bulletin 
that satisfactory concrete can be made from mixtures containing a 
wide range of ratios of sand to coarse aggregate. It is only necessary to 
add the proper amount of cement to get the result desired. 

The sieve analysis of aggregates affords a means of comparing the 
concrete making qualities of different materials, as well as methods of 
combining fine and coarse aggregates. The method of combining fine 
and coarse materials in certain arbitrary ratios, is not logical, and 
must be superseded by a scientific method of combining materials to the 
best advantage. 

* Iowa Highway Commission specifications. 



15 

The amount of cement to use for a given case should depend upon 
the quality of the concrete desired and the grading of the aggregate. 
ruder the present system of writing specifications and letting contracts, 
the character of the aggregate is seldom known at the time of writing 
the specifications. The custom has become established of making the 
amount of cement dependent upon the relation between the fine and 
coarse aggregate, such as one part of cement to 2 parts of sand to 4 parts 
of crushed stone. For such relations to mean anything, it is necessary 
that the dividing line between the sand and stone be exact. This divid- 
ing size is customarily 14 inch. The foregoing opinions on the propor- 
tioning of concrete mixtures are substantiated by the results of tests 
reported in this bulletin. 

Conclusions. The conclusions with respect to the theory of propor- 
tioning, which may be drawn from these tests are these : 

1. If the consistency remains the same the strength varies with the 
coarseness of the aggregate, or, for the same consistency, the finer the 
aggregate the more cement, (to maintain the strength) is required. 

2. The finer the aggregate the more water is required to produce the 
required consistency. 

3. And, therefore, combining 1 and 2, the more water used in mixing, 
the more cement is required to maintain the strength. 

III. PROBLEM AND DESCRIPTION OF INVESTIGATION 

The factors upon which the strength of concrete depends are (1) the 
the density of the concrete, and (2) the extent to which the particles 
are cemented together. The latter factor depends upon the amount of 
cement in a given volume, and upon the total surface area of the par- 
ticles. -.- ^'Hj 

Inasmuch as numerous authorities are agreed that the density of the 
mixture is partly, and the surface area, wholly dependent upon the 
grading of the aggregate, and that density also depends upon the con- 
sistency, or amount of water in the mixture, the writer has formulated 
the following rule for proportioning concrete mixtures : Use the best 
graded aggregate available, enough cement to make concrete of the class 
desired, and mix with the least amount of water which will yield a work- 
able mixture for the conditions under which the concrete is to be placed. 

The Problem. The problem considered in this investigation is that 
of proportioning the mixtures in which there is an excess of fine aggre- 
gate, as is true of practically every Iowa pit-run gravel. The results 
apply to either screened or pit-run gravel. 

To establish such a workable relation it is necessary to ex- 
press the grading of the gravel by numerical functions. Other experi- 
menters, notably Abrams and Edwards, have done so, and their work 
could be used as a basis for proportioning pit-run materials. However, 
both Abrams' "Fineness Modulus,*' and Edwards 7 "Surface Area" 
methods require the making of a complete sieve analysis of the material. 



16 

The method developed here requires the separation of a sample into two 
sizes only and a simple determination of the weight per cubic foot of 
the loose gravel. 

The principal conclusion resulting from the investigation is that the 
grading of pit-run gravel may be measured by the ratio of fine aggre- 
gate to total aggregate (that is, percentage of fine aggregate in total) 
and by the weight per cubic foot of the material, measured loose. For 
the purpose of commercial convenience the dividing line between fine and 
coarse aggregate is taken on the common Xo. 4 sieve. In the following 
discussion, fine aggregate as defined above will be called "sand" and 
coarse aggregate "pebbles." 

Investigations. Two assumptions have often been made by users 
in proportioning the cement to pit-run gravels : 

1. That the ratio of cement to total aggregate should be a constant, or 

2. That the ratio of cement to the sand portion of the aggregate should 
be a constant. 

The former is wrong and on the unsafe side. The latter is also wrong 
but is on the side of safety, as is shown in Tables I, III and IV. 

TABLE I. STRENGTH OF CONCEETE 

Eatio of Cement to Total Aggregate a Constant 



Percent of "Sand" in 
Aggregate by Weight 


Proportions 1 DenS ity 


Water, Per- 
cent of Dry 

Materials 


Compressive 
Strength lb. 
per sq. in. 


42 

55 
75 
95 


1:2:3 | 0.789 1 9.33 
1:2% :2% 0.770 10.65 
1:3%:1% 0.737 12.65 
1:4%:% 0.673 15.30 


1600 

1200 

920 

480 



Ratio of Cement to Total Aggregate a Constant. Table I is typi- 
cal of the strength of concretes made under the assumption that the ratio 
of cement to total aggregate should be kept constant. Further demon- 
stration of the fallacy of this assumption is not necessary. 

Ratio of Cement to Sand a Constant. The assumption that the ratio 
of cement to sand in the gravel should be constant was investigated in 
twenty-four series of tests. Materials from several localities and two 
classes of concrete were studied. Table II gives the physical character- 
istics of the aggregates used in these investigations. 

Each series comprised tests of gravels containing respectively 42, 55, 
75, and 95 percent, by weight, of sand. The mixtures were made arbi- 
trarily by combining sand and pebbles in the right amounts. The same 
sand and pebbles were used in each mixture in a series. Each series in- 
cluded tests of forty specimens. Five specimens were broken for each 
test of a mixture. Specimens from all series were tested at 28 days old ; 
specimens from some series were tested at 7 days and from others at 
six months. Specimens were 8 by 16 inch or 6 by 12 inch cylinders 
stored in water. In some of the series the No. 8 sieve was taken as 



17 



TABLE II. PHYSICAL CHARACTERISTICS OF AGGREGATES 
Materia] Used in Specimens Reported in Tables III and IV 





c 
Z 

X 

- 
- 

- 


- £ 

c . 

01 OS 
V 


-J 
3*5 


So 
gS 

& O 


"3 > 


Sieve Analysis: Percent Passing Sieve No. 


o 


1 


4 8 | 14 | 28 | 48 100 


Y\ 


1 1 


c 


Size of Opening, in. 




1.5 | 0.75|0.371|0.185|0.093|0.046|0.023|0.0116 


0.0058 


1 


9 
10 

IS 
19 
22 

23 


39.8 
39.3 
42.2 
37.9 
40.5 

45!o 
39.7 
41.2 
41.3 
42.0 
41.2 
39.3 
42.3 
40.0 


99.9 
100.7 

95.9 
103.0 

98.4 

9i.*3 

99.8 
98.8 


4.0 
2.0 
9.0 
2.0 
4.0 
1.3 
7.5 
0.8 
2 




i 1 1 


100.0 

100.0 

100.0 

100.0 

82.0 

87.0 

79.8 

85.2 

100.0 

96.4 

100.0 

85.2 

61.5 

83.9 

87.7 

87.3 

1.9 

0.8 

8.4 


67.5 
83.5 
72.5 
82.0 
58.0 
69.5 
55.3 
66.5 
87.6 
60.1 
76.6 
59.7 
35.2 
61.3 
63.7 
59.8 


25.5 
57.0 
37.0 
49.5 
23.6 
45.2 
28.2 
39.4 
43.2 
32.9 
39.3 
31.6 
17.9 
30.6 
33.7 
31.5 


6.5 

18.5 

12.0 

10.0 

5.8 

16.0 

10.0 

6.2 

11.1 

18.2 

9.7 

8.6 

9.7 

7.4 

9.1 

10.2 


1 5 


2 




1 


4.5 


3 
4 
5 




1 1 

1 1 

1 


100.0 
100.0 
100.0 
100.0 


7.0 
3.8 
1 5 


6 

7 




I 

| 


2.0 
3.8 


8 




| 1 


0.3 


11 


2.68 
2.75 
2.73 
2.69 
2.75 
2.72 
2.68 
2.66 

2 .'81 
2.82 
2.80 
2.65 


I 

1 


1.3 


12 
13 
15 
16 


101.1|1.8 
99.1 1.8 

98.7)2.0 
104.4(1.6 

98.5|1.5 
100.012.0 


I 

i. |ioo.6 


100.0 

100.0 
92.8 
98.0 
99.1 
99.4 
99.6 


3.8 
1.8 
1.2 
2.1 


17 


1 |100.0 


1 6 


20 


! 1100.0 


2.1 


21 


37.7|103.6|... 
37.51103.710.0 
41.6 98.1(0.0 
42.4|102.3|0.0 
42.4|100.0|0.0 
42.2|101.0 1.5 
37 4 102 511 


1 |100.0 

100.0 89.71 52.8 


2.1 




100.0 
100.0 
100.0 

100.0 


84.5| 24. 2| 3.7 
86. 9| 49.2 27.9 
74. 8| 31. 7| 10.3 
100. 0| 82. 5| 31.5 
64 9 1 52.5 12.7 
































1.6 
1.1 









































the dividing line between sand and pebbles. The general result was 
very similar to that obtained when the No. 4 sieve was used. 

In Tables III and IV are given the results of these tests showing the 
variation in strength of concrete with the percentage of sand in the 
gravel, when the ratio of cement to sand is kept constant. Figs. 5 and 6 
show graphically the increase in strength when the cement and sand 
ratio is a constant. 



Testing Methods, Measurement of Materials, 
were made by weight. 



All measurements 




FIG. la — THE CONSISTENCY THRUOUT THE EXPERIMENTS REPORTED 

HEREIN WAS MAITAINED SO NEARLY AS POSSIBLE BY OBSERVATION 

AT THE MEDIUM GRADE SHOWN IN THE CENTER PICTURE OF EACH 

GROUP. Cone test on left, cylinder test on right. 



18 



v'ng /h Inches 




Sieve A/umber 

FIG. 1 — TYPICAL SIEVE ANALYSIS DIAGRAMS OF COMBINATIONS OF 
MATERIALS. Sand passing No. 8 sieve, pebbles retained on No. 8 sieve. 




Sieve Number 

FIG. 2 — TYPICAL SIEVE ANALYSIS DIAGRAMS OF COMBINATIONS OF 
MATERIALS. Sand passing- No. 8 sieve, pebbles retained on No. 4 sieve. 



19 



Mixing. Specimens in Series 1 to 22 were mixed in a small Smith 
mixer. Five specimens were mixed at one time. Series la to 16a were 

mixed by hand in a mortar box. Five specimens were made at one 
time. Series 25 to 40 were mixed by hand in a mortar box. Five spec- 
imens were made at one time. Series 46 and 47 were mixed in a Bly- 
stone mixer. Five specimens were made at one time. 

Consistency. An attempt was made to bring all specimens to the 
same degree of plasticity. All were made by the same operator. The 
consistency adopted may be called medium wet. It is illustrated in 
tig nre la. 

Molding. The specimens were molded in cast iron cylindrical molds, 
resting on machined plates, without tamping. The concrete was con- 
solidated by puddling" with a rod. Before testing the upper ends of 
the specimens were capped with plaster or rich cement mortar. 

S/ei/e Ope/?/ng /n Inches 




FIG. 3 — TYPICAL SIEVE ANALYSIS DIAGRAMS OF COMBINATIONS OF 
MATERIALS. Sand passing No. 4 sieve, pebbles retained on No. 4 sieve. 

Size of Specimens. 

Series 1-22, 8" in diameter and 16" long. 

la-16a, 3 out of each batch were 6" x 12", and 
2 out of each batch were 8" x 16", 
each batch containing 5. 
" 25-40, 6" x 12" 
" 46-47, 6" x 12" 



20 



Storage. Specimens were stored in water, maintained at room tem- 
perature, and removed from water one day before tested. 

Testing. All specimens were tested upon a Universal testing ma- 
chine of 100.000 pounds capacity. 





























/ZO 


























lie 

JI6 
H4 

//z 










































































































































































<0 <N /Ob 

■5> 










































































<A) /OO 
96 
96 

























































































































































60 



/OO 



3o 4o so to 70 

fa- cent of sand in Aggregate 

FIG. 4 — SHOWING THE TREND OF VARIATION IN WEIGHT PER CUBIC 
FOOT OF PIT RUN GRAVEL WITH THE SAND CONTENT OF THE GRAVEL. 



21 



Tables of Strength and Data. Each strength value shown in the 
following tables, and each point shown in the diagrams of strength varia- 
tion, is the average resulting from five specimens. Series of tests which 



SBOO 














































































Sooo 














1/ 


















































L / 












* 

^ 2200 

Nl 

> 

^ /ooo 

% 

^ /too 

\ 

^ /400 
/200 
/OOO 

eoo 

Goo 














/ 




















































Sere 


• 






















\S^ 






















"^ 


a^ 






















C/ 


$2* 
















































$y 
















a*** 



























































































40 SO GO 70 BO 90 /oo 

for cent of \5ond ' tn Aggregate 



FIG. 5 — Showing- that, if the ratio of cement to sand is a constant, the crush- 
ing strength increases with the sand content of the gravel plotted from data in 

tables 3. 



22 



are comparable by reason of being made under the same conditions are 
grouped in the same table. 

It will be noted from Tables III and IV that if the ratio of cement 
to the sand portion of the aggregate is kept constant, the strength of the 

380O- 




<?0 50 GO VO GO 90 /OO 

P&r oenf of ' 3or?d /r? /)ggr&gore 

FIG. 6 — Same as 5. Data in table 4. 



23 



concrete will increase as the sand content increases. This is of course 
a safe procedure but it is not good engineering. It is evident that a 
correct method of proportioning materials, containing varying percent- 
ages of sand in the aggregate will call for cement somewhere between the 
amount required to keep the cement to aggregate ratio constant, and that 
amount required to keep the cement to sand ratio constant. The amount 
of cement must increase as the sand content increases but not so rapidly 
as in the tests shown in Tables III and IV. 

The tests shown in Table V were made following a preliminary study 
of the results obtained in the series shown in Tables III and IV. 
Further study demonstrated that the method by which they were pro- 
portioned was erroneous. However, the data corroborated the con- 
clusions drawn from the other tests as to the factors upon which the 
strength depends. 



SO 
$ 40 




















r 










c <4^ 








X . 




</ 


































^ 30 
















^^ 














^ 

^ 








i 

So 

70 






^^ 


> 












>^ 














^^r 





























fo 



30 



GO 



7o 



60 



90 



/oo 



Per cent 1 of *5anc/ /n /7ggrec?a/e 

FIG. 8 — THIS DIAGRAM SHOWS THAT AS THE SAND CONTENT OP THE 
GRAVEL INCREASES, THE STRENGTH INCREASES WHEN THE RATIO 
OF CEMENT TO TOTAL AGGREGATE IS A CONSTANT. Summation of data 

in tables 1-3 and 4. 



24 



C/ass / - 5and pass/ng 7/o.4 - Pebb/es reta/ned on /Ya 4 and pass/ng /'& ' 


\ 


1 


Proporf/ons 


lA/e/gh/ 
Per CaP/. 


Abso/u/e l/o/ume 
Parts ofUn/f 
/o/ume /n Green Con 


IS 


Crushing 
5rreng/h 
Lb3.per 5a In 


We/'ght 


Loose Volume 


Abso/ufe i/o/. 


Is 




si 

ll 






3 




i 
1 




! 


1 


I 

1 


M 


Age 
7Doys 


Age 
26Das. 


5 


5 


Z-4.75 


4256 


Z-3.9 


46-66 


Z-4.05 


Z-55 


/-5.5 


1/2.0 


Z47.6 


./2/ 


.264 


379 


.764 


/a 9 


/235 


/654 


/-366 


55-45 


Z-3.2 


62-5/ 


Z-4J 


/-4.3 


/-55 


ZZ02 


Z490 


J46 


.346 


.292 


.766 


//.2 


/436 


2275 


P266 


75-25 


/~2.3 


6237 


Z-3.35 


Z-3./ 


Z-4.35 


Z07.Z 


/47e 


J62 


4-26, 


J42 


.750 


Z3.9 


/637 


2Q26 


f-e/o 


95-5 


f-e 


97-5/ 


/-3.2 


Z-2.5 


/-39 


30/ 


/46J 


.209 


.493 


.030 


732 


Z4.6 


2244 


3532 


6 


6 


Z-4.75 


42-53 


7-3.0 


46-66 


Z~39 


Z-5.4 


/-5.4 


//4.8 


/46/ 


/22 


.279 


.363 


.764 


96 


/G72 


3360 


/-3M 


5503 


Z-3./ 


62-52 


/-37 


7-4.4 


/-5./ 


//23L 


/46/ 


.04 


340 


29/ 


775 


ZO.4 


/792 


3296 


f-e.66 


75-25 


P2.3 


60-27 


/-2.7 


/-3/ 


/-3.6 


/07/ 


/4/2 


J75 


.406 


./37 


.720 


/32 


2/20 


3452 


/\2JO 


95-5 


/-2 


96-5.2 


Z-27 


t-2.5 


Z-3.35 


/O/J 


74/.Q 


306 


462 


.024 


.7/2 


Z4.5 


2360 


3664 


7 


7 


Z-4.75 


42-56 


/-3.9 


5Z-66 


/-4J5 


P5.6 


/-5.6 


///3 


/46J 


J/6 


272 


362 


770 


ZZ35 


//50 


2340 


Z-3.66 


55-45 


/-3£ 


65-49 


/-4.05 


/-4£5 


/-5.3 


/07.6 


745.6 


J45 


.339 


276, 


.760 


Z2J 


/423 


2672 


P2.66 


75-25 


Z-2.4 


64-26_ 


/-3.3 


/-3/ 


/-4J 


/02.3 


/43.0 


./75 


4/0 


./36 


72/ 


Z5.0 


/550 


3245 


Z-2./0 


95-5 


Z-2./ 


96-46 


Z-335 


/-25 


7-3.6 


94.0 


/42.0 


.204 


460 


324 


706 


Z53 


2045 


366Q 



TABLE III PART 1 



S5ond Pass/ng /7o. 6 ~ Pebb/es refa/ned on 77o.6 and pass/ng /# 



IVe/ohr 









Propor-//ons 



Loose l/p/ume 












Abso/csfe fo/. 



\ 






b/e/ghf 
perCu.Pf. 



Pi 



Abso/crhe l/o/ume 
Par/s of Unit l/o/ 
in Green Concrete 



Si 



^ 



' c 



^•5 



Crush/ng 

3-rrengtH 

Lbs. per og. Zh. 



/7ge 



7Days\28Qays 



/Jge 



1-4.75 



42-56 /-3.6 



43-65 



CLAS3 '/. 



/-3.9 



/-5.6 



/-5.6 



Z/625/465 J20 



263 



366 



79/ 



/0.7 



/460 



/992 



Z-3.66 55-45 /-3.0 



63.50 



Z-3 4 



/-4.3 



/-4.6 



//4.6C/463 



J47> 



346 264 



777 //. 



/770 



2760 



P2.66 



75-25/ -2. 3 



6/~26 



/-275 



/-37 



/-37 



ZO9./0 Z460 J76^ 



4Z9 



Z40 



737/4.3 



/570 



3232 



/-2J 



95-5 /-/9 



963.0 



2.5 



/-3.0 



/02/0/43.0 



.203 



476 



024 



703 



/72 



/440 



3632 



CLA33"3. 



/-70 



42.56 /-5.7 



46.65 



7-5.6 



/-<3.3 



/-<3.3 



Z/625/453 



063 



29/ 



.400 



.774 



z/5 



720 



7346 



P5.2555r45 /-43 



63-50 



/-5.7 



/-6.4 



/-6 



//430/462 



J04 



365 



299 



766 



/2.4 



960 



/532 



/-4.0 



75-25 /-3.4 



6Z-26 



Z-4.55 



/-6./ 



/09/G /4/6 



/27 



446 



J49 



722 



75.4 



/OOO 



224/ 



Z-3./7 95-5 /-2 9 96-56 /-4.2 /~3.7 7 -5 3 ZO270 Z40.6 .Z46 . 52Z 326 697 Z76 //20 2339 



TABLE III PART 2 



2:> 



Ciass 3 - .Sand pass/nq iio. 4 - Pebbtes retained on iio 4 and passing /■£> ' 


5 


$ 

> 

1 


Proportions 


We/gbt 
Per Co. Ft. 


Abso/ute l/oiume 
Parts of Unit Voi 
in Green Concrete 


it 


Crusbinp 

Sfrengtb 

Lbs. Per 5q. In. 


tVeigbf 


Loose l/oiume 


Absoi 


jfel/ot. 






IS 


•k ^ 
to ^ 


IS 


X 




1 
1 




! 


§ 
^ 

1 


I 




A<?& 
7Days 


Ape 
26 Das. 


9 


5 


t-70 


4258 


i-59 


46-66 


t-60 


i-3.3 


i-3.3 


U2.0 


i462 


.066 


300 


.4i3 


.799 


/at 


690 


i274 


P5.25 


55-45 


i-45 


625/ 


i-54 


i-6.2 


i-7.3 


H0.2 


i474 


J09 


332 


.289 


.780 


a 6 


i065 


i779 


i-4.0 


75-es 


1-33 


62-87 


i-4 7 


i-46 


i-6.2 


/07i 


/45.G 


J3i 


460 


J64 


755 


/3.3 


i520 


i870 


K3J7 


95-5 


t-3.0 


97-5/ 


1-455 


i-3 7 


i-56 


toot 


i45D 


J56 


.550 


.028 


738 


/5.2 


i290 


2t78 


H 


c 


t-7.0 


42~58 


t-5.9 


46-66 


/-6.0 


i-6.4 


i-6.4 


H46 


i456 


.033 


292 


403 


778 


t/.i 


t060 


/920 


P523 


55-45 


t-4.4 


62-52 


/-5.B 


i-6.2 


i-72 


i/235 


i44.0 


J05 


360 


.280 


.753 


i2.7 


/376 


2U2 


i-4.0 


75-25 


t-3.6 


QO-2? 


t-4.7 


i-4.6 


t-62 


t07i 


/42.0 


J26 


443 


J59 


726 


i42 


/400 


2376 


t-3/7 


95-5 


i-e.9 


96-52 


i-395 


i-37 


i-4.9 


ton 


i4t.2 


./47 


5/2 


.028 


.687 


i765 1632 


2384 


f 


7 


i-ZO 


42-58 


i-59 


5i-66 


i-6/5 


t-Q.4 


i-Q.4 


iit.3 


i460 


.034 


.294 


408 


786 


t0.2 


732 


i282 


P5.25 


55-45 


i-46 


65-49 


t-5.6 


i-6.4 


i-77 


i07G 


/450 


705 


367 


30Z 


.774 


i/.O 


942 


teto 


i-4.0 


75-25 


i-3.7 


64.26 


t-5.4 


t-4.7 


i-6.6 


/02.3 


t45.t 


733- 


465 


J55 


753 


i32 


908 


/289 


i~3t7 


95S 


P32 


96-4.6 


i-4.6 


t-37 


i-5.5 


94.0 


/4t.O 


J53 


538 


.026 


7/9 


/4t 


t/64 


t893 



TABLE III PART 3 



Ciass i - Sand passing fio.6 — Pebbtes retained on fio. 4 and passing i'/s" 



lA/e/g/rf 









Proportions 



Loose l/oion~>t 



n 



<3 



8«* 



Abso/ufe 7b/ 






- k/e/gh+ 
PerCt/.Pt. 



«« 



Absotoie r!7oiun->e 
Parts of Unit l7oi. 
in Green Concrete 









Crusbing 

Strengtb 

Lbs, per So. In. 



Ape 
7Days 



Age 
26Days 



i-4 75 42-58 i-3.9 



67 t-3.9 



i-5.4 



i-5.4 



t/3.2 



/472 ./2t 



283 



372 .776 



no 



25t4 



P3.66 55-45 i-3.i 



6i~5i 



i-3.75 



i-4.3 



i-5.i 



iiO.4 Z46.7 J44 



338 



286 



768 



i20 



/996 



2968 



i-2.66 75-25 i- 2.4 



79.27/ -3.25 i-3.i 



7-4.2 



/O55/46.0 



i79 



4t9 



i39 



.737 



i4.5 



i8Q6 



3060 



i-2.i 



95-5 



/-2 



96-5/ i-3.0 



/-25 



/-3 7 



ton 



i43.6 



206: 



485 



025 



7/6 



/5.3 



2430 



3652 



/ -475 42-56 



i-37 5i -72 7-3.7 



/-55 



/-5.5 



i476 



720 



260 



385 



785 



iO-85 



i704 



2560 



<6 



t -3.66 55-45 



7-2.9 



65-54 /-3.5 



/-43 



/-5.05 



//83 



/445 



.340 



276 



760 



//.7 



/424 



2496 



/-266 



75-25 



/-23 



63-26 /-2<3 



/-3./ 



/-38 



it 0.6 



/44.0 



J77 



i39 



730 



/4.6 



2404 



3252 



i-2.t 95-5 /-2 96-52 / -2.7 / -25 /~3.4 i02.0 i430 .204 .482 .024 7iO i56 2672 36/2 



TABLE III PART 4 



26 



C/ass 3- Sand pass/ng /Yo d-febb/eo retained on TYo. 4 and pass/ng /''e ' 


* 




Proportions 


'Weight 
perCu.F/ 


Abso/ute l/o/urne 
ParfsofUn//7o/ 
/n Green Concrete 




Crushing 

Strength 

Lbs. per Sg.In 


tVefght 


Loose l/o/ume 


Abso/ute Vo/. 


rt 


-si 


8* 




8*1 


\ 


m 


1 
1 


^3 


\ 


"ft 

1 


! 

1 




Age 
7Das. 


Age 

28 Da 5 


2/ 


7 


7~70 


4KH» 


/-5.9 


43-67 


7-605 


/-0.4 


/-3.4 


//3.2 


/46J 


.083 


.292 


.405 


.760 


//./ 


7029 


/660 


7-525 


5^5 


/-4.5 


6/5/ 


/-55 


'-625 


7-7.45 


//0.4 


/455 


JOB 


.373 


.262 


760 


726 


//32 


2006 


7-4.0 


2?<25 


P3.6 


79-27 


/-5.4 


747 


77.0 


J05:> 


/43Q 


./32 


464 


.754- 


750 


/2.6 


/343 


2044 


7-3/7 


*5~5 


Y2.9 


96-5/ 


/-4.9 


/-37 


/-6.05 


/O/./ 


/430 


J54 


.544 


.029 


727 


/47 


/423 


2400 


22 


2 


>70 


42-3d 


P55 


5P72 


{-5.6 


P63 


/-63 


72/2 


/465 


.064 


.294 


405 


.763 


/0.9 


606 


/375 


7-5.25 


53-45 


/-4.2 


6554 


/-5./ 


7-6,2 


/-74 


7/6.3 


/46./ 


./06 


.375 


.264 


765 


/2.6 


/0/6 


/732 


/-4.0 


75-25 


7-5.5 


0326 


P46 


/~4.d 


/-63 


//0.6 


7456 


/26 


45/ 


.76/ 


740 


/3.6 


976 


7592 


7-3.77 


95-5 


/-e.9 


96-32 


7-4.6 


/-37 


7-5.05 


/020 




J49 


524 


.026 


70/ 




77/2 


7975 



TABLE III PART 5 



C/ass / - Sand pass/no TYo. 6 -Pebb/es retained on /Yo. 6 and passing /'/s " 


\ 
* 


1 


Proportion 


IVeigbt 
PerCuPt. 


Abso/ute Vo/urne 
Parts ot Oin/t l/o/. 
/n G-reen Concrete 




Crush/ng 
Strength 
Lbs. Per Sg.In 


k/eiaht 


Loose l/o/ame 


Abso/ute I7o7. 


I! 

Si 


II 


!U 
<< 


If 


V 1 £ 


1 




1 

1 


1 


1 


1 


f 
1 
1 




Age 
7Das. 


Age 
28Das. 


£ 
^ 


S. 


7-5.37 


42-56 


7-43 


47-63 


7-45 


7-6.2 


P6.2 


/72.50 


744.0 


.706" 


£77 


369 


766 


70.65 


929 


7603 


i-420 


55-45 


7-3.5 


62-49 


7-42 


7-4.9 


/-5.6 


7/235 


743.0 


J26 


.344 


.262 


754 


//.a 


7397 


7907 


7-237 


75-25 


7-2.5 


67-26 


7-3.6 


7-3.35 


/-5.05 


/0765 


74/0 


J66 


423 


.74/ 


732 


73.5 


7379 


2267 


7-2J5 


95-5 


7-20 


96r5 


7-335 


7-2.4 


7-4.75 


707.70 


7395 


.799 


476 


.025 


700 


75.5 


7935 


2665 


*5 
*> 


<h 


/-530 


42-58 


7-4:5 


46r62 


7-455 


7-6.2 


7-6.2 


77045 


7450 


.706 


.277 


.362 


765. 


7/95 


/009 


773/ 


7-4.06 


55-45 


/-35 


63-47 


7-4.2 


7-46 


7-5.6 


10690 


743.0 


J29 


340 


279 


.746 


73.4 


//22 


7653 


7-2.76 


75-25 


/-25 


87-25 


7-3.55 


7-3.2 


7-45 


703.5C 


736.0 


.769- 


407 


./36 


772 


749 


/420 


2462 


7-2.05 


95-5 


/-2.0 


96-5 


/-3.07 


f-2.4 


/-3'6 


9640 


737.0 


.796* 


453 


$25 


.676 


77/ 


744/ 


2552 


<3 


^* 


7-6.06 


42-56 


7-45' 


527/ 


7-4/5 


7-6.4 


7-6.4 


/270 


742.0 


095 


.284' 


574 


753 


77.7 


586 


7293 


7-455, 


55-45 


/-3.5 


65-53 


7-4J5 


7-5.35 


7-6.2 


/222 


740.0 


.7/6* 


.34/ 


.279 


736 


73.2 


703 


7373 


/-3.05 


7525 


P2.5 


64-28 


7-3.65 


P3.6 


/-5.4 


//5.0 


7300 


J55* 


4/7 


\/39 


7/7 


755 


600 


/776 ' 


P2.24 


95-5 


/-2.0 


97-5 


7-3.5 


/-2.6 


/-4.5 


7052 


7365 


■/66* 


466 


7)24 


680 


7dO 


7030 


2260 



TABLE IV PART 1 



27 



C/ass/ ~ Sand pas s/ing Po. 4 - Pebb/es. reta/ned on Pa 4 and pass/no /£>.' 


1 

<«3 


1 


Proportions 


Weight 
PerCuPt. 


Abso/ute l7o/ume 
Parts oP Unit 14/ 
tn Green Concrete 


is ~^ 
A .5, 


Crushing 

Strength 

Lbs. Per Sg. In 


Weight- 


Loose Vo/ume 


Abso/ute At>/ 




\V,Ju 

OK 








\ 




* 




In 

! 


5S 

1 


1 

! 


it 


Age 
7Das. 


Age 

26 Das. 


ft 


^ 


f~S36 


48-56 


P45 


46-66 


t-4.5 


pets 


P6./5 


i/8.0 


/440 


J06 


.274 


.379 


.759 


tt.9 


626 


1873 


P4/3 


55-45 


P5L5 


62-5/ 


P4.05 


P4.67 


P5.50 


U0.7 


/420 


./26 


.336- 


.276 


740 


/es 


636 


/402+ 


f£Q5 


75-85 


P85 


68-87 


13.45 


P3.09 


P4.53 


t07i 


i372 


J73 


4oe 


./33* 


.706 


/46 


660 


/399 


P2./3 


95-5 


/-8.0 


97-5 


/-eso 


pes 


P3.56 


too./ 


/372 


J9P 


453- 


.024 


.666 


/6.4 


986 


/964 


s 


K 


P534 


42-56 


P4.5 


5P66 


P4.5 


P626 


t-eeo 


fff.3 


i436 


J03+ 


278 


375 


.750 


/3.0 


69/ 


/408 


Mat 


55-45 


135 


65-49 


P4J 


P4.7/ 


P5.48 


/076 


Z4/.3 


J87+ 


.389 


.269 


.725 


Z4.65 


734 


/646 


/-e.75 


75-85 


P2.5 


6486 


P3.3 


P3.8 


P4/5 


/oe.3 


/377 


J68 


333 


J30 


.660 


/75 


739 


/482 


P20 


95-5 


t-eo 


965 


P3.8 


pe.34 


P3.79 


94.0 


/36.0 


J97* 


439 


033 


.659 


/0.7 


660 


toee 


5 

fc 


<o 


1-545 


48-50 


P4.5 


46-67 


P4.56 


P6.38 


P6.38 


t/3.6 


/44.0 


J04 


.879- 


365 


.766 


me 


36/ 


/052 


z-4.ee 


55-45 


135 


68-58 


P37 


P4.92 


f-5,/6 


i/3.2 


L408 


J84 


335 


275 


734a 


tee 


456 


/267 


P290 


75-85 


P8.5 


68-86 


P3.4 


t-3.4 


P4.52 


i09.0 


mo 


tee 


4t2 


/3d 


7/2 


/5.0 


6/2 


/636 


P2./7 


95-5 


t-BO 


97-5 


P2.75 


PZ54 


P3.43 


toeo 


/350 


too* 


453 


.024 


.665 


/70 


398 


/782 



TABLE IV PART 2 



C/ass 3~ Sand pas-sino L1o.&-Pebb/es retained ontio.6 and Dossing /&-" 


1 


"ft 
1 


Proportions 


IVeight 
Per Cu.Pt. 


Abso/ute Vo/ume 
Parts oP Unit l/ot. 
in G-reen Concrete 




Crushing 
Strength 
Lbs. Per Sg. In. 


U/eigh-t 


Loose l/o/ume 


Absolute Vot. 






II 






X 




! 


?! s 


! 


>o 

1 




0^ 


Age 
7Das. 


Age 
28Das 


ft 


- 


P6.40 


42-56 


P7 


47-63 


P7/ 


t-9.6 


t-9.6 


//2.50 


/453 


.078 


.296 


407 


.775 


tt.7 


508 


768- 


P6.00 


55-45 


t-5 


68-4S 


P6.2 


P70 


P8.55 


//235 


Z43.5 


.094 


362 


.297 


.753 


/es 


523 


//74 


P457 


7325 


t-4 


6P86 


P5.6 


P5.33 


P737 


/0785 


/40.4 


J/5 


460 


J53 


786 


Z3.35 


665 


/3/d 


P3.22 


95-3 


t-3 


96-5 


P49 


P3.6 


t-e.t 


tot.to 


Z36.8 


./45 


580 


.028 


.693 


/345 


694 


/387 


ft 

i 


*i 


/-623 


42-56 


P7 


48-62 


P7t 


P9.6 


P9.6 


//0.45 


Z43.5 


.078 


.29/ 


40/ 


.764 


tt.7 


376 


78/ 


P5.7P 


55-45 


t-5 


63-47 


/-6.8 


P6.76 


P905 


/O6.90 


/43.0 


.097 


.360 


296 


.753 


te.5 


463 


937 


t-440 


75-25 


P4 


6P25 


P5.9 


P5./6 


/-75 


L03.56 


/398 


.//7 


453 


95/ 


.78/ 


/4.0 


6/6 


//53 


P3.08 


95-5. 


/-3 


96-5 


P5.0 


P36 


Z-5.93 


9640 


/365 


J48 


504 


.027 


.679 


te.7 


789 


/39/ 


ft 
4 


> 


P9.4& 


42-56 


P7 


58-7/ 


/-782 


/-//./ 


/-/// 


t87CC 


Z4/.7 


.068 


890 


400 


.758 


tee 


228 


479 


/-6.50 


55-45 


P3 


6555 


t-6.46 


P765 


/-96 


/2880 


/38.8 


.084 


.354 


283 


786 


/3.3 


363 


690 


P469 


75-25 


P4 


64-28 


/-60 


P575 


P84 


//5.od 


t34.6 


./04> 


446 


J50 


.702 


/33 


40/ 


846 


P3.36 


95-5 


t-3 


97-5 


P5./ 


P394 


P6.5 


/O5.eo 


/335 


J39 


.520 


.086 


.687 


t53 


446 


/077 



TABLE IV PART 3 



28 



C/ass 3 ~ Sand pass/ng /Yo. 4 ~ Pebb/es retained on /Yo. 4, pass/ng /'/e'.' 


1? 


1 


Proportions 


We/ghi- 
phrCu.Pt. 


Abso/ute l/o/ume 
Parts orUnt't l/o/. 

' in Green Concrete 


it 


Crushing 

Strength 

Lbs. Per So. 7n. 


Weight 


Loose Vo/i/me 


Abso/ote yo/. 


u 

OX 














t 
1 






! 


1 
1 




Age 
7Das. 


Age 
26 Das. 


fc 

$ 


^ 


78.34 


4258 


77 


46-66 


/-705 


/-97 


797 


t/2.0 


/365 


.069 


.23/* 


.369 


.739 


t07 


266 


54/ 


75.90 


55-45 


75 


62-5/ 


/-67 


769 


/-9./ 


//0.7 


/370 


.092 


.349 


.266 


727 


t/6 


402 


676 


f-4.56 


75-25 


/-4 


6Z-27 


/</ 


75.35 


76.05 


/07./ 


/360 


.///■<- 


446 


/4d 


705 


t46 


326 


960 


73/9 


95-5 


/-3 


97-5 


/-ST 


73.76 


f-70 


/00J 


/355 


J43 


5/0 


.027 


j630 


/6.3 


403 


//66 


* 
* 


N. 


78.30 


43-36 


/-7 


5Z-66 


/-70 


/-9.J 


/-9.7 


//3.3 


/455 


.073 


.297 


4/0 


760 


7/0 


345 


967 


(-5.75 


55-45 


/-5 


65-49 


/-6J 


76.74 


/-6.05 


/076 


/43.0 


.097 


.359 


.294 


750 


/2.6 


4/6 


/080 


P437 


75-25 


/-4 


64-26 


/-5.4 


75/ 


7675 


/02.3 


/40.3 


J/6 


452 


/50 


720 


/43 


573 


/377 


/-3.0Q 


35-25 


/-3 


'96-5 


7-455 


/-35 


75.25 


94.0 


/35.0 


750 


499 


.026 


.675 


/6.7 


63/ 


/556 


^5 


•0 


76.50 


42-56 


/->? 


46-67 


/-705 


t-9.67 


79.67 


t/3.6 


/477 


.074 


307 


423 


304 


9.2 


4/3 


1136 


76.02 


55-45 


/-5 


62-52 


/-5.05 


P753 


/-70 


//3.2 


/420 


.066 


364 


.296 


750 


//./ 


460 


/2/6 


74.65 


75-25 


74 


62-26 


/-4.9 


7-5.43 


7655 , 


/09.0 


/425 


7/5 


469 


756 


740 


/3.3 


437 


//90 


73.26 


95-5 


73 


97-5 


/-3.9 


73.62 


/-4.9 


/02.0 


/36.0 


743 


520 


.027 


.690 


/5J 


604 


/336 



TABLE IV PART 4 



C/ass / - Sand passing /Yo. 6 ~ Pebb/es reta/ned on /Yo. 6 passing /7s " 






Proportions 


We/gh/ 
PerCu.Pt 


Abso/ute l7o/ume 

Part of LZn/t l/o/. at 

*5<2-t Concrete 


IS 


Crushing 
Strength 
Lbs. Per So. In 


IVe/gbt 


Loose l7o/urne 


Abso/ute l7o/. 




^0. 










fa 


I 
1 


<*> 

Ss 

^3 


1 
1 


<0 


X 




Age 

26Das. 


Age 
671os. 




- 


76/7 


33:67 


75/ 


392747 


7435 


76.96 


7672 


Z/4.25 


/4750 


397 


229 


446 


.772 


9.04 


26/0 


39Q0 


75.54 


42-56 


74.5 


5/0-655 


745 


76.23 


76.23 


756/ 


/46.00 


J05 


283 


374 


762 


9.76 


2650 


3620 


74.58 


55-45 


73.6 


66.O-JQ.0 


74/ 


75.22 


75.67 


//3.50 


/4450 


J20 


.352 


275 


747 


/0./5 


23/0 


3700 


73.5/ 


75-25 


/-3J 


MM6P 


73.65 


/-4.0 


74.7 


/0625 


/4/.00 


743 


435 


.136 


7Z6 


/270 


2740 


4070 


7270 


95-5 


726 


%0-4& 


73.55 


73./4 


742 


976/ 


/3900 


Z66 


503 


325, 


696 


/430 


2660 


3960 


£ 

^ 


^ 


/-6/6 


3367 


75/ 


510745 


74.65 


76.97 


76.7 


//375 


/465C 


397 


.232 


444 


773 


6.66 


2540 


3700 


Z-5.65 


4256 


1-45 


5/5-67o 


745 


7625 


76.25 


77.6/ 


(455 


J05 


264 


373 


762 


962 


2660 


3/70- 


7456 


55-45 


73.6 


65.0-438 


74.07 


75.20 


75.57 


73.00 


/430 


720 


350 


2Z3 


743 


/040 


2350 


3390 


7356 


7525 


/-3Y 


mm 


73.6 


1-4/ 


74.6 


/06./2 


/405 


J4Z 


439 


Z40 


720 


/255 


2560 


3790- 


i-2.7/ 


95-5 


72.6 


975-4.6 


7356 


73/5 


74.25 


96.3/ 


/385 


766 


.505 


.025 


396 


Z430 


3000 


4/20 


K 


^ 


76.05 


33-67 


75/ 


3657SJD 


74.6H- 


76.6 


764 


///.37 


/465 


.099 


.229 


444 


772 


640 


2700 


3530 


75.43 


42-58 


74.5 


47.0-692 


74.5 


76./ 


76/ 


t/343 


/465 


706 


£62 


376 


766 


9/0 


2700 


4000 


74.45 


55-45 


73.6 


60/h405 


7425 


75/ 


75.7 


//0./6 


7455 


724 


355 


.276 


755 


/0.20 


3030 


4/00 


73.60 


75-25 


/-3/ 


81.0-26.4 


7354 


74/3 


752 


/09.00 


/435 


744 


452 


Z44 


740 


//.55 


3000 


43/0 


72.90 


95-5 


1-2.6 


96550 


737 


73.4 


J-4.7 


/04.66 i 


/425 


/65 


530 


.027 


722 


(3.65 


2950 


4660 




55 


Z-6.24 


33-6? 


75/ 


35.570/ 


743 


770 


76.7 


//5.0 


/46.0 


.096 


.226 


446 


766 


6/6 


2260 


32/0 


75.57 


42-56 


745 


493-662 


745 


763 


76.3 


7625 


/45.0 


704 


230 


375 


759 


8.9/ 


2620 


3660 


t-453 


55-45 


7-33 


627495 


7435 


75/ 


75.5 


72.00 


/430 


720 


344 


272 


736 


/050 


2700 


3950 ' 


7356 


75-25 


/-3./ 


083-26.7 


73.57 


74/ 


f-47 


/0650 


/40.5 


.Z40 


43Z 


J40 


7/Z 


/2.60 


26/0 


3420 


P2.76 


955 


726 


96.0-5. 


735 


73.25 


74.2 


99.70 


Z39.2 


Z66 


496 


.025 


.669 


Z4.60 


2730 


3600- 



TABLE V PART 1 



29 



C/ass / ~ Sand poss/ng O/o 4- - Pebb/es retained on /Yo 4 passing /'/e ' 




% 

Xj 


Proportions 


Weigh* 

Per Cuff. 


Abso/ute l/o/ume 
Parts of -Unit l/o/. 
ofCreen Concrete 


I! 


Crushing 
dfreng/h 
Lbs. Per 5? In 


k'eighf 


Loose i/o/ume 


Abso/ute fa/. 


w 

\ 1 










1 
3 






^ 5! 


1 


1 


^ 
?. 


5^ 


Age 

26 Das 


Age 

627os. 






v~V 


_-:-v" 


v" 


57-52 ~.A~ 


772 


t-€P75 


.920 


45P 


.093 


229 


445 


765 


792 


2/90 


2400 




--V/ 4256 ,75 52.550 -542 


t-es 


f-65 


PPPP 


ASS 


JO/ 


205 


.373 


759 


947 


2332 | 3/30 


> vs 


-AT.' 5545 75 .02470 -405 


/-54 


/-e.o 


&43 


#50 


J/7 


355 


275 ' 747 


//.0 


2677 3e20 




_,-- - fJf .j -j=-f C -j -jj> 


/-43 


t'54 


//343 


'4& 


J36 


449 


.42 \729 


'2/ 


2930 4000 


v.v _J-"-_-" _V r~V-/-' -J"^ 


/-335\ 74.3 


/0437J4C7 


,63 


.52/ 


.026 \ 7/0 


/4J 


3300 ' 4/69 


1 


-.V^-r-^- -/ .3:vV: <rr 


2695 


-eo~ 


/i425\/453 


Q96 


227 


440 j 763 


6.2 


2730 


3/60 


-JV ^ 4255 -'/ -JLVT" --'-' r 


26.3 


i-69 


//6/2<247C 


J05 


Asc 


.375 769 


63 


26/0 


3340 


--V- -V -'^ -A- c2 -5 9 -47" 


753 


76/ 


//A 662462 


J22 30/ 


.262 \ 765 


945 


3060 4/30 






-5 05 735 7- *cU.~J. , -42 


/-455 ' ■ -A 'A 


57 ~ 725 


32 ^50 A3 733 


tO 7 


3 090 ! 4/20 


L 755 Pf-S 76 _?r-JV 1 /-_27 


755 1 M6 


■A3 '2 A 5 


.'67 225 ' 02c ' 7/5 


/29 


3320 | 4530 






AjvP J_'v ~~ A JLf. - z=if ' -4^ 


2657 


/-so> 


/09.67\/437 


.096 


2. >£ ! 426 1 742 


65 


2450 


2960 


/-.vV -"-'-"j - " --'/ ~'s 75 o --72 


-22 


f-6.0 


//200 \/45€ 


JOG 


275 


37/T734 


92 


2430 


3050 


^ 


S J 


24? 55-45 -55 554-55. -A3 


-SPA 


756 


PA -A' 


,24 \347 


2^6 ' 749 


/06 


2660 


3420 


V 


. -ppp 775 -j "25-2^0 -ac 


■407 


hS3 


PPPP A5c 


A3 ~P: <5 ''As' 


//6 


3/90 


4/00 


2P2~ 957 -55 P~PS- -57 


/-JJ3 


74.3 


,'PesA AAs 


. 35 •■ 52^ i 227 ' .7/9 


/25 


34/0 


4/20 




vj; _vv~ -jf 55P--^5 -455 


77/ 


/-e.4 


: '3.93 ~sP\ PA<P 223 ' 44 ' ! 760 


3.9 


2360 


2630 


52: -'_'-j\f --'_' ~PP~c~£ --'-V 


/-6,3 


t-63 


tfj&56 /4£2 


24 200 i 374 ! 756 


9.7 


2500 32/0 


. ~V „" .:jf<f -Jr 027-5.5 -A 2 


252 


1-5.6 


J/3.73 45 C 


J20 I 350 • 376 746 


0.35 


2925 3430 


-A PA 775 -A 55.Q-2Z7 -35 


,'-48 


1-58 


,'f/.67j43C 


/40 445 j J43 


726 


//75 


3//0 ] 3970 






-220 As -AP 05 575 -565 


7323 


745 


/0/.37\/4/.C 


J66 \3/0 \.C26 


70S 


/3.9 


3350 £?60 



TABLE V PART 



C/ass 3 ~ Sand poss/na /Yo. 6 ~ Pebb/es retained en /Yc 6 and pass/ng /'/& ' 


1 

.J; 




Prcporf/ons 


lA/e/ghf 
PerCuPf 


Abso/ute l/o/ume 
Parts of Unit fa/ 
of Green Concrete 


In 

Z. s 


Crushing 
Strength 

Lbs ferOgln 


l>/e.gnr 


Loose IJo/ume 


Abso/ute l/ot. 












I 








1 


! 


X 

1 

1 




Age 

26Das 


Age 
627os 


- 


- 




33-67 


V95 


397-750 


2767 


- 7 


7/09 


//42A 


4:5 


060 


£36 


465 


763 


22s 


.230 


725 


/-662 


~32s 75 52-05- 


27.0 


799 


,'-9<S 


//535[A2A 


269 


29/A-334 \744 


222 


760 


555 


P-eAO 55 A5 50 657-497 v- 


2762 


/-66 


73.5 \/527\ 


POA 


.359 \ 26/ '724 


-2 


.450 


327 


-~:~~-A25 -455s~P^-s -25 


-204 


-2 


2232 As 4 


.07 


456 1 J46 | 7// 


2^2 


2~2 


2242 


1-364 \ 95-5 | 235 \930-4.5\ 25.65 




2695 


27 550 


/32 


524 \ £26 232 


AAP 


527< 


522. ' 


S 


^ 


/-/C.3 


OO-O^ 55 3-274 P- 'P 


/-//5 


HOJ 


2py\ <J 93 


259 ! 232 ' 449 ' 7AC 


656 


7/3 


725 


2670 


A25A -V 52-067 72 


2/0.0 


-22 


^55 5P-..0 P.~ 2:? J: -7 


9.22 


.0/2 


-/.-- 


2673 5545 -56 242 A J7 266 


2773 


-955 




---; 5.-^ ;-' -'- 


55 


A22 


3AP 


;-5P 7575 A55sAA26.A -04 s~A 


f-Q4 


05. P 252 


. 54 457 '45 76 


57 


525 


2022 


-Ac 6 05-5 55 P~2A5 -63~ -J^ 


1 7c 


PPP 22 


55 , 529 027 222 






A222 


n 


^ 


'-2 2 APA- , -:5 PPc^AA 


/73 


/-//4 


4-0/ 


27 


452 


.06/ 233 


462 ' 756 


764 


.023 


445 


2545 C255 -7 473-643 


270 


79.5 


29.5 


2 A3 


445 


.07/ 


266 


367 1 744 


955 


//7C 


690 


1-2.52 55 45 -50 6P -A5A -065 


77.33 


263 




s - 


-" 


55s 52 ^ 75 


PAP 


/0/5 \ 2340 


/-504 7575 -4555 P2c " P. 


75.7 


26/ 


fO - j- - 


J07 1 459 1 45/ \ 7/7 




2390 '1 95-5 ■ / -35^962-45 -540 


-4_4i 


26.9 


/24 C 272 5 


? » 


557 , 520 5P5 




::~ 


0752 


- 


^ 


2/04 \33~67\ 265 


3a&753\ 276 


- 7 


2/0.6 


4 ' 


556 


230 


453 | 742 


252 


776 


3'95 


i-6.65 


42-58 270 


49/-659\ 270 


-966 


'-99 


'5 4. 7 


067 


AcA 


575 7B0 


5 


.-.- 


27 


2600: 


5545 | /56 


623-495\ 269 


2756 


294 


720 \/395 


.064 355 1 262 1 72/ 


2 


2 3 


- - ' 


/-503 


75-25 


S-4A0 


623-264 


2626 


2527 


/-625 


/POO 525 


.24 44c 44 c'-V 


225 


/670 


.... 


/-370 


955 


/-3.5 


952-45 


263 


/-423 


2 76 


PJ7 P-55 


J30 \ 523 027 £60 


.'435 


/740 


0570 



TABLE V PART 3 



30 



C/ass J - Sand passing Tio 4 ~ Pebb/es retained on 7/o 4 and pass/hg l/e" 




[ 


Proport/ons 


Weight 
PerCu.Pt. 


Abso/ate l/b/ume 
Parts of Un/7 Vo/ 
of Green Concrete 




Crus/iing 

Strength 

Lbs. PerSqJn. 


Weigh/ 


Loose l/o/ume 


Abso/ute I7o7. 








<0 t < 


Si* 


x 


M 

1*1 


1 






1 






Tige 
26Das 


Tlge 

677os. 


K 


*> 


7/070 


3367 


/~65 


392-7)0/ 


7-6.36 


7-/22 


79.20 


7/9.06. 


7432 


.050 


242 


466 


766 


722 


7790 


/550 


7-6.95 


4256 


/-70 


50.0-696 


7767 


/70./5 


7-/0/5 


72000 


7465 


070 


307 


404 


76/ 


6.05 


/625 


2460 


7 695 


33-45 


75.6 


633324 


7-666 


7-766 


/-94 


7/6.43 


7455 


067 


365 


296 


770 


695 


/560 


2660 


7-525 


75-25 


7435 


645264 


754 


7-67 


774 


77343 


7400 


703 


476 


750 


729 


//3 


/660 


2660 


/366 


953 


/-35 


96.3-32 


756 


7-4.5 


7-77 


/0437 


39.0 


.73/ 


562 


7)26 


72/ 


ZZ6 


/926 


3000 


& 

^ 


!Q 


H03 


33-67 


P03 


362-767 


7-6.63 


7-776 


7-92 


7/425 


743.0 


06/ 


24/ 


465 


767 


663 


/325 


/930 


/-665 


4256 


/-70 


495-674 


770 


7-90 


7-96 


7/6/2 


7450 


372 


304 


400 


776 


769 


/400 


2065 


7-663 


55-43 


7-5.6 


64-05/6 


766 


7-76 


/-92 


Z/4.66 


/453 


067 


363 


297 


767 


906 


2/60 


3000 


7527 


7325 


74.35 


666265 


7-67 


76/ 


7-6.4 


773.67 


/43.0 


706 


490 


755 


757 


/0.2 


2250 


3200 


7364 


93-5 


735 


9953/6 


766 


74.5 


7-6.6 


70372 


335 


730 


555 


C26 


7/3 


/2.6 


2590 


3740 


R 


5§ 


P975 


3567 


705 


346736' 


7-633 


7//0 


7-67 


/0967 


/407 


062 


229 


454 


745 


77 


/3/0 


/470 


76.35 


42-56 


/-70 


45J-65.0 


7-6/9 


7-94 


7-94 


7/2.0 


/44J 


073 


292 


393 


753 


6/5 


/600 


2370 


7-6.62 


55-45 


756 


563-496 


7-6.6 


7-74 


7-9.2 


///06 


/45.0 


090 


370 


.295 


755 


9.3 


/925 


2670 


7-575 


75-23 


7433 


766-274 


7-64 


7-57 


7-6.5 


70906 


7435 


J/7 


477 


755 


743 


70/ 


25/0 


3360 


7396 


93-3 


/-35 


97.0-533 


75.66 


7-45 


7-76 


/0656 


'425 


J33 


.570 


529 


722 


107 


2640 


3740 


| 


^ 


7-/05 


33-67 


733 


369-77? 


'7-664 


7-777 


796 


'593 


74/0 


559 


233 


457 


749 


76 


/260 


/640 


7-6.7 


42-3Q 


770 


497-677 


7-69 


7-96 


7-96 


77656 


/426 


970 


.293 


.390 


753 


645 


/430 


mo 


7 -676 


55-43 


736 


63.65/2 


7-6.75 


7-775 


/-9.S 


Z/3.75 


743.0 


.066 


.366 


290 


744 


ZOO 


/665 


2420 


7-5.76 


73-23 


7435 


65718.0 


7-6.7 


7-5.9 


70.3 


7/7.67 


740.C 


J05 


466 


750 


723 


77.2 


2/50 


2960 


7-36 


93-3 


733 


9623/ 


7-5.6 


74.33 


1-72 


/0/.67 


7375 


357 


540 


.on 


.696 


729 


2400 


3230 



TABLE V PART 4 



IV. THEORY FOR MAKING CONCRETES OF EQUIVALENT 

STRENGTH, USING GRAVELS OF VARYING SAND 

CONTENT — THE "SAND" METHOD 

The Theory. The theory of the "sand" method is based upon the 
assumption that there is a direct relation between the strength of con- 
crete and the ratio. 

c c 

l- (c + s + p) ~~ r^d 

in which c = absolute volume of cement, s = absolute volume of sand 
particles, and p ■= absolute volume of pebbles in a unit volume of freshly 
made concrete ; d = coefficient of density = absolute volume of solid ma- 
terial in a unit volume of freshly made concrete = c + s +P ; and 1 — d 
= volume of air and water voids. By absolute volume of a granular 
material is meant the actual sum of the volumes of all of the particles; 
it is expressed as the fractional part of the total space occupied by the 
material. 

This principle was presented with reference to sand mortars in 1897 
by R. Feret, Figure 9 is plotted from researches published by Mr. 
Feret in Bulletin de la Societe d' Encouragement pour V Industril 
Nationale 1897, Vol. II. 

Figures 10-11-12 corroborating the correctness of the principle are plot- 



31 



640O 



3600 



5ZOO 



43O0 






44C0 



^ 400O 
& 32oo 

I 

1 

I 



Z4oo 



^ *£»£? 



/#*? 



/200 



0OO 



400 



/ 

_____ 0/ 

0/ 

o-X- 

/ 

/o 

c 



./ .2 



C 



.9 /.o 



t-Cf 



FIG. 9 — RELATION OF CRUSHING STRENGTH TO THE CEMENT-VOIDS 
RATIO OF THE CONCRETE. From data published in 1879 by R. Fert. 



32 



35Q0 


































































































































o 


/a 






























































































Ol 
























3000 


























o^ 




Q 










































5 


o; 














































n o / 









































D C 


5 



























$ 


















( 


t? 


6^ /a 

-1 /° 

























«5 8500 




















n° 


/° 













































"9 


I 


























\ 























°l 










































01 


J 


i 


























3 














°< 


c 




r > 




























>£ eooo 

1 
















< 


j 












































<•?„ 




o| 








































^ 


* u 














































<9 U 


o 
































«5 















c 


' 














































r w ( 


c> 









































o 










































5j 




nO 












































& 




°k 




D° 








































<S 




o A 












































^ IOOO 




J 












































/T 
























































































K 


































































































300 























































































































































































































































































i 





















/-d 

FIG. 10 — RELATION OF CRUSHING STRENGTH TO CEMENT-VOIDS 
RATIO. SERIES 25-40. 



33 

































































































































































































































































































































































.$ 








































































































































o 














































o 


/ 


f 










^ 

a 
































o 






\° J 














































$ 












































o 


Yd 


4 














































of 
















"$ 2000 

I 

1 

$ /SOO 










































































n 






n 








































o 


o 












































o 






o 


n 


o 






































h° 








o 








































°/ 












































u 








o 
























1 

v /OOO 






























































1 


3 


t 




o c 


t> 








































o 







uo 
















































D U 











































/( 


1 o 










































o 


/< 


) 




































^ 





































































































soo 






















































o 




































































































































































































/i 



















































5 
c 



/-d 



.G 



FIG. 11 — RELATION OF CRUSHING STRENGTH TO CEMENT-VOIDS 
RATIO, SERIES 1A TO 16A. 



34 



40OC 






























































































































































































1 
o 


> 
of 








3500 



















































































- < 


) 












































o 




















% 


































< 


)° 


/ 





































































































o 










X 
















































































( 


)/ 








< 


) 






I 






































o 












vl 




































































































^ 


















































^ 






















l 


> 



























I 






















O 
















o 












$ 
























(h 








o 








































\ 


!y 




o 




































< 


> 






6\J 


/ 1. 


> 
























I 
















o 




A 


f 






o* 






















k 




1 














1 


jj 































5 

^ taoo 

i 




















Jf 




D JL 












































< 


) 

























































































o 


















































rO 




> 






























^5 

















































































































































































































































































































































































































l-d 



FIG. 12 — RELATION OF CRUSHING STRENGTH TO CEMENT-VOIDS 

RATIO, SERIES 1-24. 



35 

ted from the data accumulated in the tests reported in Tables III and 
IV.* The tests grouped on each diagram are comparable by reason of 
being made from the same cement, similar materials and subjected to the 
same conditions as to making, molding and curing. Each point is 
derived from the average of tests from 5 specimens. This relation 
is further verified by tests by the U. S. Bureau of Standards, reported 
by Wig, Williams and Gates in Technologic Paper No. 58. A diagram 
similar to figures 9-10-11-12 plotted from this data is published in John- 
son's "Materials" rewritten by Professor M. 0. Withey. 



Application. Assuming that 



d 



should be equal for concretes of 



equivalent strength, new proportions were computed for each of the 
series of tests shown in Tables III, IV and V. In each series the new 
proportions were computed so as to be equivalent to the oue containing 
42 percent of sand. That is, the proportions were adjusted for each 



percentage of sand to make the computed value of 



1 — d 



equal to the ac- 



tual value of 



of the mixture containing 42 percent of sand. The 



1 — d 

method of computation is illustrated as follows : 



DATA CONCEENING PEOPOETIONS FEOM TYPICAL SEEIES (NO. 30) 



Percent of Sand in Aggregate, 


c 


s 


P 


d 


c 


by Weight 


1 — d 


33 


0.096 
0.105 
0.122 
0.132 
0.167 


0.227 
0.286 
0.361 
0.456 
0.525 


0.440 
0.378 
0.282 
0.145 
0.026 


0.763 

0.769 

0.765 

.0.733 

0.718 




42 
55 
75 


0.455 


95 





















In order to arrange the proportions for equivalent strength it is nec- 
essary to so change the relation between the absolute volumes of cement 



and the aggregate that the ratio 



will in each case become equal 



to 0.455. The adjustment can be made by increasing or decreasing c 
and decreasing or increasing s -f- p, so that d will be unchanged. 

Let c', s' and p' be the new values required for c, s, and p, respec- 
tively. As explained before, these values are the percentages of absolute 
volumes of materials in a unit volume of freshly made concrete. 



1 



(c' + B'.+ p') 



0.455 



* This principle is further corroborated by Prof. A. N. Talbot. Proceedings Am. Soc. for 
Testing Materials 1921. 



36 

Therefore, to convert the mixture containing- 33 percent of sand : 

d = .763, therefore 

1^0763 = ° A55 
c' =0.108 
d = c'4-s / + p' 
0.763=0.108+ (s' + p') 
(s' + p') =0.655 

Accordingly the ratio of absolute volume of cement to absolute volume 
of total aggregate, required to make a proportion using the 33 percent 
sand mixture equivalent to the 42 percent sand mixture is : 

10S :655, or 1 :6.7 

New proportions on a basis of absolute volumes for the 55, 75, and 95 
percent mixtures were computed in the same way. 

This theory is approximate, not rigorous, for when the concrete is ac- 
tually made, the density d will be affected a small amount. The result 
obtained, however, is within the probable range of accuracy in the mak- 
ing of the concrete. 



TABLE VX COMPUTED PROPORTIONS 

Computed Proportions Required to Produce Concrete Equivalent in Strength to the 
Mixture in Each Series Containing 42 Percent of Sand 

(a) Division Between Sand and Pebbles y x " 



Series 


Based Upon 
c 


Proportions by 


Weight for Percent of Sand 


No. 














1 — d 


33 


42 


55 


I 


95 


o 


.000 

.555 
.504 
.428 




1:4.7 
1:4.7 
1:4.7 
1:7.1 


1:4.8 
1:4.8 
1:4.8 
1:6.2 


1:3.7 
1:3.1 
1:3.5 
1:5.8 


1:3.3 


6 




1:2.9 


7 




1:3.2 


13 




1:4.8 


14 


.374 
.392 
.264 
.332 
.378 
.440 
.452 
.448 
.420 




1:7.2 
1:7.2 
1:8.3 
1:8.3 

1:8.4 
1:5.3 
1:5.4 
1:5.4 
1:5.5 


1:6.1 

1:6.2 
1:7.7 
1:6.8 
1:6.0 
1:4.7 
1:4.6 
1:4.4 
1:5.1 


1:5.2 
1:5.8 
1:6.8 
1:5.7 
1:5.6 
1:3.8 
1:3.6 
1:3.8 
1:4.6 


1:4.2 


15 




1:4.7 


13a 




1:6.0 


15a 




1:4.2 


16a 




1:4.1 


5a 




1:3.2 


7a 




1:3.1 


8a 




1:2.9 


29 


1:5.7 


1:4.1 


30 


.455 


1:5.2 


1:5.4 


1:5.2 


1:4.9 


1:3.9 


31 


.439 


1:4.8 


1:5.1 


1:4.9 


1:4.5 


1:4.1 


32 


.430 


1:5.5 


1:5.4 


1:4.9 


1:4.4 


1:3.8 


37 


.319 


1:7.8 


1:8.7 


1:8.0 


1:6.3 


1:6.0 


38 


.321 


1:7.8 


1:8.3 


1:7.8 


1:7.2 


1:5.8 


39 


.301 


1:7.4 


1:8.0 


1:7.8 


1:7.2 


1:6.5 


40 


.283 


1:8.2 


1:8.3 


1:7.9 


1:7.1 


1:6.1 



37 



TABLE VI (Continued) 





(b) 


Division Between San 


d and Pebbles %" 




Series 


Based Upon 1 


Proportions by Weight for 


Percent of Sand 


No. 


33 


42 


55 


1 « 


i 




l — d — li 


J 95 


2 


.575 |.. 


| 


1:4.8 


1:4 1 


1-3 1 


1:2.6 
1:4.5 


10 


.367 .. 


| 


1:7.1 


1:6.8 


1:5.2 


la 


.453 [.. 


| 


1:5.3 


1:4.9 


1:4.3 


1:3.5 


3a 


.451 L. 


| 


1:5.3 


1:4.8 


1:3.8 


1:3.1 


4a 


.385 .. 


I 


1:5.4 


1:5.3 


1:4.6 


1:3.8 


9a 


.320 .. 


| 


1:8.3 


1:7.3 


1:6.3 


1:5.2 


11a 


.305 .. 


1 


1:8.2 
1:9.4 


1:7.7 

1:8.2 


1:6.4 
1:7.2 


1-5 


12a 


.261 .. 




1:5.5 


25 


.441 


1:5.7 1 


1:5.3 


1:4.8 


1:4.0 


1:3.6 


26 


.441 1 


1:5.7 1 


1:5.3 


1:4.7 


1:4.1 


1:3.6 


27 


.462 1 


1:5.5 


1:5.2 


1:4.9 


1:4.4 


1:4.0 


28 


.432 | 


1:5.7 1 


1:5.4 


1:4.7 


1:4.0 


1:3.6 


33 


.269 | 


1:9.3 | 


1:8.3 


1:7.5 


1:6.9 


1:5.9 


34 


.255 


1:8.6 | 


1:8.5 


1:8.0 


1:7.2 


1:6.5 


35 


.277 


1:8.6 1 


1:8.1 


1:7.6 


1:6.9 


1:5.9 


36 


.246 | 


1:9.0 | 


1:8.4 


1:8.0 


1:7.0 


1:6.5 



(c) Sand %" Down; Pebbles y x " Up 



„ . 1 Based Upon 
Series 


Proportions by Weight for Percent of Sand 


No. c 


33 | 42 


55 


75 




1 — d — 


95 


21 | .377 

22 1 .387 | 

17 1 .540 

18 | .558 


1 1:7.2 | 

1 1:7.1 1 


1:6.3 | 1:6.0 
1:6.3 | 1:5.4 
1:4.3 1:3.6 
1:4.3 1:3.2 


1:5.2 
1:4.3 


1 1:4.6 


1:3.2 


1 1:4.7 1 


1:2.9 











The proportions thus derived are by absolute volumes. To make 
these proportions usable it is necessary to convert them to a weight basis. 
Assuming specific gravity of cement = 3.15, and that of the aggregate 
= 2.68, absolute volume proportion of aggregate (cement = 1) may be 
changed to weight proportion by the following equation : 

Aggregate (weight) = aggregate (absolute) X ^p^ 

= aggregate (absolute) X -85 

Table VI shows the proportions by weight as computed for equivalent 
strength. Figure 13 shows graphically the relation between propor- 
tion for equivalent strength and percentage of sand in the gravel, for 
each series independently. 

The conclusion drawn from a study of these diagrams is this : The 
relation between proportions by absolute volumes to give equivalent 
strength, and sand content of the aggregate, varies uniformly and at 
approximately the same rate for all degrees of quality of concrete. 
The line AB in the diagram 13 is established to indicate this rate 
of variation as an average. 



38 



To make use of this diagram to determine the proportions to use with 
a given aggregate having a certain sand content, it is necessary first 
to assume an aggregate and proportion known to be satisfactory. Locate 



/■0O 



§1 



5p ' 



.« 







l-OO 
























'<$ 


/■'70 








^ 


"vv* 
















^)/:30 


































1^^^" 


























cr-" 
















/:30 




















^*> 






/.eo 


























/■/O 


























i 


? / 


s 


O £ 


'O 4 


o 




to 


& 


? 


O 


&. 


& 


/c 


K? 





Per oent of sand in Aggregate 



FIG. 13 — THIS DIAGRAM SHOWS THE RATE OF DECREASE IN THE 
RATIO OF CEMENT TO TOTAL AGGREGATE NECESSARY TO PRODUCE 
CONCRETE OF EQUIVALENT STRENGTHS IN EACH SERIES OF TESTS 
AS THE SAND CONTENT OF THE GRAVEL INCREASES. Plotted from 

data in table 6. 



39 

the point representing this known condition and draw a line through 
it parallel to AB. Then pick from this line of proportions the proportion 
corresponding to the given aggregate. 

To make a single line diagram of general application, the line AB 
Fig.13) is plotted on figure 14 using for ordinates the decrease in parts 
of aggregate, and for abscissas the increase in percentage of sand in the 
aggregate. This diagram can be used for determining proportions 
in ease the proper data are at hand, or for writing a table of propor- 
tions for equivelent mixtures of cement and pit-run gravels in general. 
Such a table could not be exact for all materials, but it would give very 
reasonable proportions to use with Iowa gravels. 



* 



s. 



».8 









** 

































X 












































A 






















• 


r 














































( 


i 







30 



4C 



SO 



60 



70 



GO 



Per Cenr Tn crease /n So/id Cbn/enr of Grave/ 

FIG. 14 — THEORETICAL DIAGRAM FOR DESIGNING CONCRETE MIX- 
TURES CONTAINING VARIOUS PERCENTAGES OF SAND IN THE 
GRAVEL, EQUIVALENT TO ANY PREDETERMINED BASE MIXTURE. 



Use of Method. To determine the amount of cement to use with 
a given pit-run gravel to yield a concrete equivalent to a given mixture 
of sand and gravel : 

1. Reduce the proportion of the standard mix to the basis of weight. 

2. Determine from figure 14 decrease in parts of aggregate corres- 
ponding to increase in percentage of sand in aggregate and change the 
proportions accordingly. 

Formula for computing item 2. (See Figure 14) 

4.0 



tana 

v = x tan a 



= .05 

= 0.05 x 



Example. Assume that an aggregate containing 42 percent sand, 
and weighing 112 lb. per cu. ft., makes a satisfactory concrete in the 



40 

proportion 1 :4y 2 loose volume. What proportion should be used with 
a similar gravel containing 75 percent of sand and weighing 107.1 lb. 
per cu. ft. ? 

Change the proportion 1 :4% to a proportion by weight thus : 

Assume 94 lbs. cement = 1 cu. ft. 
1 cu. ft cement to 4.5 cu. ft aggregate 
= 94 lbs. cement to 4.5 X 112 lbs. gravel, 
4.5 X 112 



= 1 lb. cement to 



94 



. :. proportion by weight = 1 to 5.36 

The increase in the percentage of sand is 33. From the diagram, the 
corresponding decrease in parts of aggregate is 1.6. Therefore the 
proportion to use for the gravel containing 75 percent of sand should 
be 1 to (5.36 — 1.6) *= 1 to 3.76. 



ft 



/-a 
V-7 

/-6 
/-S 
/-+ 
/-3 
/-2 
/-/ 






C/assZ 

C/ossf 
C/ass7/l 



fer cent of Sonet in /Aggregate 

FIG. 15 — PRACTICAL DIAGRAM FOR PROPORTIONING MIXTURES CON- 
TAINING VARIOUS RATIOS OF SAND TO COARSE AGGREGATE, AR- 
RANGED FOR FOUR COMMON CLASSES OF CONCRETE. Proportions by 

weight. 



If it is desired to measure the materials by volume instead of 
by weight change the above weight relation to a loose volume proportion 
as follows : 

Wt. per cubic foot of cement = 94 lbs. 

Wt. per cubic foot of gravel = 107.1 lbs. 

1 lb. cement to 3.76 lb. gravel 

t= 94 lb. cement to 354 lbs. gravel 

= -Q-T- cu. ft. cement to— — cu. ft. gravel 
= 1 to 3.30 by loose volume 



41 





Proportions for ffir Run Grave/ Concrete - C/ass 1 


rso — 


^Z S "Nr V ^V S "V ^ 




S \ V S V \ S X 


v 


-> S \ \ \ ^ Y ^ ^ 





S V \ S_ \ ^ S \ ^ 


h; 


£■ -S,- J*. -S Y V ^c -a^ V 




v v s- t v s 5 >„ a ^ 


^ 


^ \ \ ^c- \ \ S s^ _v \ 


,5 


x \ s S V \ v ? ^s 5 


Vj 


* \ \ \ ^ VyV V. Y V ^ 


s 


\ \ x % x s ^6- St s; 5 \ 


\t'° 






\ \ \ \ \ >-fe* fe V V Y -t- 


>Q 


\ \ \ \ \, %w\ X S S T 


\j 


^ S \ V ^k- £ ^c- \ ^ ^ 




S ^ \ ^* X V ^ V Y 


M /oo 


X *> V^^ ^ S Y * 


1 


V s r 5 % \ 5,- S \ S \ 


? 


-^ Ss. § V S S Y ^S % 


k 


V^\ ^ \ \ S \ * 


rS^a 


SIS,. \ 5.- X v ^ 5_ 




> s r \ s \ Y % S 


S 


^ ^c-% V \ ^e\ ^ -r+- 




/Assume !S ^ \ Ns N ^_ ^ ^ 


^ 




*/* 


Grave/ - Z.&6 X^ ^ ^ S ^._!s 




W-r P*rCu Ft. Cemen/= 94 /6a. s^S^. \ \ ^ S^ 












X N sK X \ \ 


7oLU 


± . IKN^Y Y 

30 40 SO 60 70 f) 90 /OO 



/%r Cen/ <5or?e/ in /Aggregate 

FIG. 16 — VOLUMETRIC PROPORTIONS FOR MIXTURES OF VARYING 
SAND CONTENT CLASS ONE CONCRETE. 















P 


''Opor 


//ons 


/ 


'or 


/= 


)/ 


A 


on 


Grave/ Co 


ncre/e 


- C/o36 


2 


























\ 




s 


s 




s 






s 






V 


s 




^v 




^ 


N 
































s 




s. 




\ 






\ 






\ 






\ 


s 




\ 






\ 


















-v. 
















\ 














\ 






\ 






s 






s 






\ 





























s 




\ 










s 






s 






\ 






N 


S L 




\ 






%- 




























s 




\ 










\ 












s 






S 






\a 




% 





























v 














\ 






\ 




s 






\ 


^_ 


\ 


^> 


S 














N* 






























s 












N^ 




S 




\ 


1 


V . 












g 












S 




















s 














, 


\ 


< 




K ; 


v v 














I 








> 








\ 












\ 














r, 






\. 


S s 












^ 












s 












s 












s 






\/ 






SS 






1 \ 














g//0 
















"v. 


S \ 






















\ 






N^ 


V 


> 








N, 




























s 


s„ 


\ 






















S 


Dk 














\ 












5 






















\ 


















x r 




^ 














^"» 












Nj 
























\ 










s 


S 




s^ 






\ 












V - 












1 


























s 










^ 


< 










S 




s 






\ 












J0'°" 


































<5 


^ 








s 






\ 




\ 


N ^ 


\ 












§ 
































V 


\ 


L? 


s k 








s 






s 




\ _ 














V) 






























s < 


, 


§ 


s 


s 








s 


v 


\ 




^_ 


\ 












^> 
































r 










s 








3 




\ 


V 


s \ 












^5e- 






























\ 




^ 






s 








s 




^. : 


s 














| 






























■v 










V 




^; 




\ 


^ s 


s 












>r 


1 








































s 








^s . 


V » 




















fissume 
Spzc/f/c Grav/ty- Cemzh/- 3./S 
» •> - Grave/ ' 2(0 
W+perCu. Ft Ceman/: 94/6s. 


















X 




N 


*v 


\ 












t 


















s 










\, ! 


^. ^ 












^jj 


















N 










v. 




























^ 


s 






\ \ 






























■ 






s 


^^s 






















%c 


■xse Yo/um<z5) 












± 






N 




^^_ 


s s 
























































i i 






•> 


.5„ 


s 












7<?- 












































1 i 






N ^' 


^ - 













4o So 6q 7o SO 

f&r Can/ iSarx/ in rfggrega-nz 
FIG. 17 — SAME AS 16, CLASS TWO CONCRETE. 



42 



A general formula for changing' from weight to volumetric propor 
tions is as follows : 

Let a = parts of gravel to 1 part of cement by weight 

b = weight of gravel in lbs. per cubic foot measured loose 
94 lbs. = weight of one cubic foot of cement 

x £= parts of gravel to 1 part cement by volume 
94a 



Diagrams. The diagrams in figure 15 have been arranged for con- 
venience in proportioning gravel concrete both screened and pit-run. 
The diagrams show proportions by weight, but they can be easily con- 
verted into volumetric relations as has just been shown. 

Propor/ ions for Pi r Pun Grave/ Concrete - C/ass 3 



I 



I 



I 











*~^ 


"s 




'{ 


A 


\ 


\ 






\ 


:^\ 


\ " 


























s 




S s 


\ 




N 




X 


V ^ 


\ . 




























\ 




V 






s 




"x s 


*- N- 
























X 


s 




\ 


\ 








X, 


_ \\ 


V 


**&- 


























s 






\, 


's 






*- V 


%^_ 


s 






















\ 






N • 


\ 










% ^ 


V^ S^ 


























s 


s 


S s 












_ s ^ 


X^ * 
























\ 




\ 


•V 


s, s 


N, 




X 




-X ^ 


^ ^£- 


























S 




S s 












is, 


^£^X 




























■s 


s, 


v. 










N s ^ 


5 - 




V 


























\ 


, S « 


"^ 


•s 




\, 








V 




























s. 


s, 




X 




v s^ s 






s \ 




























^s 








N 




^ s 


































\ 






X 


^§s» 


N ^s 




































X 




Nn 


^1*^ 


^ S ^- 


\ 


\ 


































X 




V < 


^S ^s 


N, 


, \ 




































^s 




^ S v 


X v 


\ * 






































!^*N 


X N 


, \ 


, V 








































N ^ X- 


x^ 


\ s 








































^ * i 


v N 


X 








































^x\ 


C-V 


V 










































s s '* 


s X 


















Assume 






^S 


s \ 


N 


















Specific Grav/fy-Cemant' 3.15 _ 








N 


O* 


















« - -Grore/' £.60 - 








V 


v V 


















Wf. per Co. Ft Cement' 94- /b& 










s \ 














































/oose yo/vmee) 




































































J 









1 


SO- 






fiO 




70 


eo 




?o 


/ 


oo 







Per Cen/ Sancf /n flggreoofe 

FIG. 18 — SAME AS 16, CLASS THREE CONCRETE. 



Class 1-A gives the proportions used by the Iowa Highway Commis- 
sion for single course concrete pavement, strength 3000 to 4000 lbs. per 
sq. in. 

Class 1, is suitable for reinforced concrete in general, watertight con- 
crete, and base course of 1st class pavements, strength 2400 to 3000 
lbs. per sq. in. 

Class 2, is suitable for first class foundations, gravity section piers and 
abutments for bridges, strength 1800 to 2400 lbs. per sq. in. 

Class 3, is suitable for large foundations and heavy mass work in gen- 
eral. It should range in strength from 1200 to 1800 lbs. per sq. in. 



43 



The diagrams in figures 16, 17 and 18 are arranged for field use 
in quickly arranging proportions for pit-run gravel on a volume basis. 
They are derived directly from figure 15. 

In applying this theory for proportioning 1 pit-run gravel it should 
be noted that the method applies only to mixtures ranging from 33 to 
100 percent sand in the gravel. 

V. VERIFICATION OF THEORY 

The system of proportioning, based upon the sand content of the 
aggregate as developed in Chapter IV has been used in practice and 



TABLE VII. 



PIT-EUN GRAVEL CONCRETE PROPORTIONED BY THE 
SAND METHOD 











Characteristics 








Com- 
pres- 




Ser- 


Ma- 


Mixed Aggregate 


Proportions 


c 


Per- 
centage 


Con- 








Sur- 








sive 


crete 

Class 


ies 
No. 


te- 
rial 


Per- 




Fine- 


face 
Area, 




By 


By 
Loose 


of Wa- 


Str'gth 


cent- 


Weight 


ness 


By 


Abso- 


1 — d 


ter in 


at 28 








age of 


lb. per 


Mod- 


sq. ft. 


Weight 


lute 


Vol- 




Mix, by 


Days, 








Sand 


cu. ft. 


ulus 


per 100 
lb. 




Vol- 
ume 


ume 




Weight 


lb. per 
sq. in. 








33 


113.9 


533 


819 


1:6.06|1:6.6 11:5 


0.374 


10.0 


1479 








42 


114.7 


501 


978 


1:5.49|1:5.92|1:4.5 


0.414 


10.0 


1945 








55 


117.5 


458 


1220 


1:4. 9711:5. 87 1:4.0 


0.403 


10.6 


2425 


I 


48- 




65 


115.7 


424 


1398 


1:4. 61)1:5. 6 [1:3.75 


0.426 


10.3 


2465 








75 


113.6 


392 


1575 


1:4. 23|1:4. 60 1:3.5 


0.428 


10.9 


2565 








85 


109.3 


360 


1753 


1:3.78|1:4.10|1:3.25 


0.433 


11.3 


2580 




I 


CO 


95 


106.9 


327 


1931 


1:3.4111:3.2 [1:3 

1 1 


0.434 


12.3 


2160 




f 


6 


33 


113.9 


[ 533 


819 


1:7. 2711:7. 90|1:6 


0.308 


10.1 


1343 




m 


42 


114.7 


501 


978 


1:6.71 1:7. 28|I:5. 5 


0.340 


9.6 


1920 




1 


<D 


55 


117.5 


458 


1220 


1:6.2511:6.79 


1:5.0 


0.343 


10.2 


1800 


II 


i 

49- 




65 


115.7 


424 


1398 


1:5.54 1:6.01 


1:4.5 


0.363 


10.3 


1955 




Q, 


75 


113.6 


392 


1575 


1:5.1411:5.58 


1:4.25 


0.367 


10.6 


2135 








85 


109.3 


360 


1753 


1:4.65 1:5.06 


1:4 


0.356 


11.7 


2005 






AT 


95 


106.9 


327 


1931 


1:4.26 1:4.63 


1:3.75 


0.373 


12.4 


1860 




f 


6 


33 


113.9 


533 


818 


1:8.78 


1:9.52 


1:7.25 


0.269 


9.4 


1113 






Z 


42 


114.7 


501 


978 


1:8.54 


1:9.26 


1:7.0 


0.284 


9.5 


1318 






■d 


55 


117.5 


458 


1220 


1:8.13 


1:8.82 


1:6.5 


0.270 


9.9 


1415 


III 


50- 


ri 


65 


115.7 


424 


1398 


1:7.38 


1:8.14 


1:6 


0.287 


10.1 


1416 






ill 


75 


113.6 


392 


1575 


1:6.95 


1:7.54 


1:5.75 


0.263 


11.2 


1225 








85 


109.3 


360 


1753 


1:6.40 


1:6.93 


1:5.5 


0.263 


12.3 


1059 




. 


c<f 

CM 


95 


106.9 


327 


1931 


1:5.87 


l:6.38|l:5.0 


0.260 


13.7 


1031 






6 


33 


115.6 


494 


756 


1:6.15 


1:6.8 


1:5 


0.447 


8.8 


3120 






42 


115.0 


468 


915 


1:5.50 


1:6.3 


1:4.50 


0.490 


8.6 


3290 


I 


46 < 


« 


55 


114.4 


431 


1142 


1:4.87 


1:5.53 


1:4.0 


0.536 


8.8 


3260 








75 


112.5 


374 


1495 


1:4.16 


1:4.73 


1:3.5 


0.602 


9.3 


2970 




. 




96 


| 102.5 


320 


1839 


1:3.27 


1:3.8 


1:3 


0.604 


10.8 


3090 






O 
CM 


33 


115.6 


494 


756 


1:9.22 


1:10.3|1:7.5 


0.231 


7.7 


2000 






6 


42 


115.0 


468 


915 


1:8.56 


1:9.7 11:7.0 


0.293 


9.1 


1810 


III 


|47- 


55 


114.4 


431 


1142 


1:7.91|1:9.0 [1:6.5 [0.316 


9.25 


1950 






1 


75 


112.5 


374 


1495 


1:6.88)1:8.0 |1 :5. 75|0.334 


10.6 


1580 




1 I 


OQ 


95 


102.5 


320 


1839 


1:5.45|1:6.3 |1:5.0 0.371 


11.0 


1760 



44 

found to give concordant results. The reasonableness of the method is 
well demonstrated in the following independent instances. 

(1) Laboratory Tests, Iowa State College. Table VII shows lab- 
oratory tests made for the purpose of verifying the method, the tests 
were made in all respects in a manner similar to those shown in Chapter 
III. The same consistency was. maintained throughout. Series No. 48, 
49 and 50 were made about one year after series No. 46 and 47, from 
different materials, and by a different operator. The consistency was 
approximately the same in both groups. 

(2) Laboratory Tests, United States Bureau of Standards. The 
following discussion and tables verifying the "sand" method of pro- 
portioning pit-run gravel for concrete, are taken from the discussion 
(by G-. M. Williams and Watson Davis, both of the U. S. Bureau of 
Standards), upon a paper concerning the proportioning of pit-run gravel 
presented at the 1919 meeting of the American Society for Testing 
Materials. 

Mr. G. M. "Williams and Watson Davis (by letter). — With the object of testing 
the method of proportioning pit-run aggregates proposed by Mr. Cram, the tests 
presented in this discussion were made. 

The tests reported in Table I (VIII, of this bulletin) were designed to duplicate 
the tests in series No. 48 in Table IV, (VII) of his paper so far as possible with 
Washington materials. Those reported in Table II (IX) are based on series No. 
47 in the same table (VII). 

In making the tests reported in Table II (IX) of this discussion, sands of the 
same gradation as Mr. Cram's sands Nos. 2, 5, and 12 were used in combination with 
% in. Potomac River gravel. These sands were made by recombining in proper pro- 
portions local river sand which had been separated on the proper sieves. 

Table IV (XI) gives the properties of the local aggregates used. Compressive 
strengths reported are the average of tests of three 3 by 6-inch cylinders stored in 
the damp closet. The weights per cubic foot reported and used are 95 percent 
of the packed weight obtained by filling a measure in layers one-fourth its height 
and jolting each layer about ten times. This figure has been found to be prac- 
tically equal to an average of the weight of poured-in unjolted material and the 
packed weight. 

Concretes within each series were of equal flowabilities as determined on the 
' ' flow table. ' ' This apparatus which measures flow or ' ' consistency, ' ' operates 
by jolting a measured mass of concrete a given number of times so as to cause the 
mass to flow or spread concentrically outward. The increase in diameter of the 
concrete is a measure of the flow. The mixes of Tables I (VIII) and II (IX) had 
a flow of 180 percent (1.8 times the original diameter), which may be described as 
a wet road consistency, while the mixes of Table III (X) had a flow of 200 percent, 
which is a suitable consistency for reinforced concrete work. 

In general, the strength results obtained in the tests made indicate that the pro- 
posed method of proportioning pit-run materials produces concretes of practically 
equal strength when the aggregates of these tests are used, and equal flowabilities 
are obtained. 

It should be noted that concretes of Table I (VIII) are comparable and should 
give equal strengths according to the theory. The same is true of the concrete 
of Table II (IX). In table III (X), concretes made with the same numbered sand 
should give equal strengths according to the proposed method. The strength results 
seem to indicate that, generally the method of proportioning gives strengths that 
are practically the same. When the sand in the aggregate is less than 50 percent, 



45 



there is an indication that the method is not so satisfactory as in the sandier mixes. 
The method seems to give slightly higher strengths for the sandy mixes, and it is 
probable that the slope of the curve in figure 3 (13) of Mr. Crum's paper could 
he decreased (mixes made leaner). The present slope is on the safe side, however. 

It should be noted, however, that the proposed method of proportioning as used in 
practice does not in any way depend upon or use the assumption that strength 

is a function of • 



TABLE VIII. STEENGTH OF CONCEETES 
All Concretes Have the Same Flowability of 180 Percent 





Weight lb. 
per cu. ft. 


Proportions 




Water Per- 


Compressive Strength 


of Sand 


by Loose 
Volumes 


c 


cent by 
Weight 


lb. per 


sq. in. 




7 Days 


28 Days 


33 


118.2 


1:5 


0.412 


8.50 


1305 


2030 


42 


121.6 


1:4.5 


412 


9.22 


1500 


2150 


55 


118.5 


1:4.0 


0.402 


10.32 


1685 


2510 


65 


116.9 


1:3.75 


0.399 


10.77 


1610 


2410 


75 


114.8 


1:3.5 


0.399 


11.42 


1540 


2355 


85 


112.4 


1:3.25 


0.396 


12.12 


1600 


2435 


95 


107.4 


1:3 


0.407 


13.11 


1710 


2780 



TABLE IX. STEENGTH OF CONCEETES 
All Concretes Have the Same Flowability of 180 Percent 



Percent 
of Sand 


Weight lb. 
per cu. ft. 


Proportions 
by Loose 
Volumes 


c 


Water Per- 
cent by " 
Weight 


Compressive Strength 
lb. per- sq. in. 




7 Days | 28 Days 


33 | 118.2 
42 121.6 
55 118.5 
75 | 114.8 
95 107.4 


1:7.5 

1:7 

1:6.5 

1:5.75 

1:5 


0.295 | 8.17 
261 9.17 
0.277 9.94 
0.236 11.95 
0.245 14.01 


675 
630 
710 
590 
610 


1245 
1380 
1470 
1310 
1320 



TABLE X. STEENGTH OF CONCEETES 
All Concretes Have the Same Flowability of 200 Percent 



Crum's 
Sand 
No. 


Per- 
cent of 
Sand 


Weight 

lb. per 

ft. 


Proportions by 


c 


Water 
Percent 

by Weight 


Compressive 
Strength 


Absolute 
Volumes 


Loose 
| Volumes 


lb. per sq. in. 


7 Days 1 28 Days 


Ml 


50 
75 
95 


122 
114 
105 


1:7.63 
1:6.18 
1:5.02 


1:5a 
1:4.33 

1:3.82 


0.319 
0.300 
0.288 


11.82 

14.22 
16.78 


940 

870 

1055 


1700 
1580 
1830 


M 


50 
75 
95 


114 
113 

107 


1:7.13 
1:5.68 
1:4.52 


1:5a 

1:4.02 

1:3.39 


0.372 
0.361 
0.376 


10.78 
12.39 
13.62 


1018 
1285 
1480 


1830 
2330 
2500 


12 11 


50 
75 
95 


119 
116 

109 


1:7.43 
1:5.98 
1:4.82 


1:5a 

1:4.12 

1:3.54 


0.356 
0.321 
0.335 


10.62 
12.86 
14.72 


1180 
1240 
1310 


2135 
2100 
2330 



a A 1:5 mix was assumed for the 50 percent sand concretes and the proportions for 
the 75 and 95 percent concretes computed by Fig. 3 of Crum's paper. 



46 



TABLE XI. CHAKACTERISTICS OF AGGREGATES 








Per- 
cent- 
age of 

Voids 


Weight 
lb. per 
cu. ft. 


Sieve 

No. 

Opening 

in 0.75 


Sieve Analysis: Percent Passing 


Aggregate 


1 4 

0.375|0.185 


8 14 
0.093|0.046 


28 
. 023 


48 
0.046 


100 
0.0058 


Potomac River 

Sand 
Potomac River 

Gravel % in. 


35.4 
39.6 


106 
99 


100.0 


1 
100. 00| 97.2 

1 
47.4 | 3.0 


87. 0| 76.6 

1 
1 


57.6 


17.2 


4.4 











(3) Pavement Base, Belmond, Iowa. Table XII shows the results 
of strength tests upon specimens of pit-ran gravel concrete, made during 
the course of construction of pavement base at Belmond, Iowa in 1919. 
Specimens were 6" x 12" cylinders. 



TABLE XII 



Percent Sand 


Proportions 


Slump Inches 


Age When 
Tested Days 


Crushing 

Load lbs. per 

sq. in. 


75 
75 
75 
75 
75 


1:3% 
1:3% 
1:3% 
1:3% 
1:3% 


1 
1 
1 

1 
1 


30 
30 
30 
30 
30 


1620 
2425 
1660 
2160 
1880 


Average 


1949 



That this concrete is substantially equivalent in strength to the stand- 
ard 1 :2 :3y 2 mix it was designed to equal, is demonstrated by the fol- 
lowing test results on specimens made from the top course of the same 
pavement, all other conditions being the same. 

TABLE XIII 



Proportion 


Size of Coarse L, T . 

Act- Slump Inches 


Age When 
Tested Days 


Crushing 

Load lbs. 

per sq. in. 


1:2:31/2 
1:2:3% 
1:2:31/2 
1:2:31/2 
1:2:31/2 


%" to 1/4" 
%" to 1/4" 
%" to %'' 
%" to 1/4" 
%" to %'' 


1 

1 
1 
1 
1 


30 
30 
30 
30 
30 


2175 
1933 
1820 
1980 
1780 


Average 


1938 



(4) Single Course Concrete Pavement, Iowa Primary Roads, 1920. 
Tables XIV and XV show comparative strength tests of specimens 
made upon ten concrete paving jobs in different parts of the state. Each 
two results represent one day 's work. The specimens were 6" x 12" 
cylinders made and cured as nearly as possible in the same way as the 
pavement. As might be expected of specimens made in this way, there 
is a wide variation in the strength of individual specimens, but the 
average values show a satisfactory uniformity from county to county. 



47 

With respect to strength and uniformity, the data indicate that the 
method of proportioning used will give equivalent results. One variable 
by which the range in strength may be explained was' the fact that the 
specimens shown in this table were made during- September and October, 
and some were therefore made under rather adverse weather conditions. 
The specimens shown in column 1, were made under the least modern 
method in use. The material was quite variable and contained many 
oversize rocks. The gravel was strung along the sub-grade and measured 
in wheelbarrows. The two pit-run gravel jobs (Columns 2 and 3) in 
which the material was handled from large stock piles and accurately 
measured were the most uniform of all. 



TABLE XIV. STEENGTH TESTS— FIELD SPECIMENS 

From Paving Projects under Supervision, Iowa Highway Commission, 1920 

Age Approximately 3 months 



1 


! 2 


1 3 


1 4 


5 


6 


7 


8 


1 » 


10 


Pit-run 

Gravel 
Piled on 
Sub- 
grade 


Pit-run 

Sand 70 

Percent 

Stock 

Pile 


Pit-run 

and 

Gravel 

1-2.4-2.4 

Stock 

Pile 


Sand 

and 

Gravel 

L-2.5-2.] 

Stock 

Pile 


Sand 

and 

Gravel 

l-2.5-l.( 

Stock 

Pile 


Sand 

and 

Gravel 

) 1-2-3.5 

Stock 

Pile 


Sand 

and 
Gravel 
1-2-3.5 

Stock 
Pile 


Sand 

and 
Gravel 
1-2-3.5 
Stock 

Pile 


Sand 

and 
Gravel 
1-2-3.5 

Stock 
Pile 


Sand 

and 
Gravel 
1-2-3.5 

Stock 
Pile 


3110 


| 3640 


3460 


3540 


4630 


3710 


1 2940 


3890 


4265 


5120 


2975 


3715 


3570 


3460 


4310 


3500 


2960 


2960 


4520 


5230 


1215 


3355 


4340 


3990 


3600 


3540 


4030 


3530 


3430 


4240 


4810 


3780 


4230 


4310 


4030 


3880 


4130 


4310 


4000 


4870 


4380 


5080 


4630 


2970 


3890 


4040 


4170 


4060 


3375 


4130 


4060 


5120 


4030 


3780 


3920 


4240 


4910 


3310 


4970 


4060 


3040 


4210 


4060 


2530 


3280 


2820 


5050 


4060 


4700 


4030 


3460 


3990 


3350 


3780 


3250 


2120 


4940 


4140 


5020 


4100 


3250 


| 4100 


3710 


3210 


3350 


3950 


4240 


3990 


4170 


4700 


3390 


4770 


3850 




3600 


3850 


4160 


4140 


4060 


4940 


2830 


4030 
3610 
3890 
3990 
4240 
3780 
3710 
3640 
3710 
3640 
3140 
3210 
3530 
3350 


4170 
3820 
3570 
3670 
3530 
3460 
3420 
3950 
4520 
3170 
3640 
3780 








3500 
3000 
3920 
3670 
2900 
2930 
3250 
3000 
2930 
3350 
2580 


3670 
3950 
3920 
3990 
2930 
3280 
5160 
4340 
3320 
4030 
3140 
3350 
4840 
4660 


4130 
3600 
3640 
3570 
4240 
4520 
4340 
4270 
4140 
4170 
3530 
3140 
4030 
4210 
3420 
3420 
3740 
3320 
3920 
3850 


2860 


2760 






2080 
4730 
3890 
3810 
4240 
4090 
3920 
3290 
3920 


3045 


2360 






2410 


2580 






2650 








2820 


2370 






2680 


2470 






2580 


3040 






3070 


2400 






2190 


2720 






2470 


3000 






2930 


3070 








2720 


2150 










3280 


2330 












3140 














2750 




































3180 




























1 


















1 
























3070 


3890 


3810 


3510 | 


3786 j 


3660 


3600 


3870 


3990 


3460 



48 



Columns 3 and 4 show results on mixtures made from screened mater- 
ials proportioned by the method described in this bulletin. Column 5, 
shows a mixture a trifle richer than the method would require. The 
numbers above the columns refer to the same jobs in each table and in the 
diagrams following. 

Figure 19 shows graphically the data in tables XIV and XV, the 
projects being arranged in the same order. 

Figure 20, shows the range in variation in the composition of the ag- 



TABLE XV. STRENGTH TESTS — FIELD SPECIMENS 

From Paving Projects under Supervision, Iowa Highvray Commission 

Age approximately 6 months 



1 




2 I 


3 1 


4a 


4b 


5 I 


6 I 


7 




Pit -run 

Gravel 
Piled on 
Sub-grade 


Pit-run 

Gravel 

70% 

Sand 

1:3% 

Stock 

Pile 

Road 

Mix 


Pit-run 
Gravel 

plus 

Gravel 

1:2.4:2.4 

Stock 

Pile 

Road 

Mix 


Sand 

and 

Gravel 

1:2.5:2.1 

Stock 

Pile 

Road 

Mix 


Sand and 

Gravel 

1:2:3.5 Stock 

Pile Road 

Mix 


Sand 

and 

Gravel 

1:2.5:1 

Stock 

Pile 

Central 

Mix 


Sand 

and 

Gravel 

1:2:3.5 

Stock 

Pile 

Road 

Mix 


Sand and 

Gravel 

1:2:3.5 Stock 

E^ile Central 

Mix 


4980 


2820 | 


4760 | 


4170 


4380 


3180 


4210 


5260 


4200 | 


5360 


4420 


4660 


2580 


3670 


3920 


5190 


3390 


3990 


3610 


4200 


4310 


3850 


4030 


4210 


3620 


4940 


4160 


3460 


3350 


3320 


4100 


5300 


3530 


4240 


3530 


3210 


4450 


4280 


4560 


4520 


4020 


3750 


4100 


4340 


3890 


3210 


4060 


4880 


3390 


4380 


4170 


3750 


4340 


4310 


4480 


3780 


3000 


4030 


4760 


3390 


4520 


4620 


3780 


3890 


3990 


4520 


4450 


2720 


4060 


3670 


4730 


4450 


3180 


2930 


3810 


5440 


4520 


4090 


2720 


4410 


4030 


4270 


3250 


4340 


3810 


3600 


5120 


4490 


3210 


3570 


4410 


3640 


4520 


3030 


3810 


3570 


2960 


4810 


4190 


3640 


2720 


4810 


3890 


4130 


3350 


3460 


4030 


3320 


4170 


4030 


3950 


3810 


5300 


3430 


3670 


4490 


4060 


3710 


2890 


4700 


4060 


3430 


3390 


4410 


3460 


4490 


3710 


4770 


3500 


3320 


5300 


3890 


2970 




3960 




4130 


4760 


4130 ( 


4600 


4490 


5330 


3780 


3140 




4200 




4700 


4240 


3750 


4370 


4450 


4910 


2830 


4310 




4690 




4520 


5720 


3950 


5500 


3140 


4310 


2890 


3990 




4480 




3670 


4940 


4700 


5050 


3950 


4910 


4480 


3750 




5160 




4590 


5760 


3890 


4630 


3950 


5160 


4770 


2930 




5840 




4090 


4810 


3640 


4310 


4240 


4810 


3990 


3280 








3960 
3110 
3670 
3640 
3390 
3530 
3710 
3460 
4060 
3530 
4340 
4100 
4170 


3780 
3420 
3780 
4700 
3740 
3820 
4450 
4380 
3600 
3530 
3560 
3850 
3610 
4130 
3500 


2820 


3600 
4030 
3890 
3920 
2360 
3990 
3810 


4100 


4940 
4130 
4630 
4200 
5010 
4520 
4560 
4420 
3290 
3640 
3710 
4270 
4030 
3530 
4910 


4170 


3320 








4700 


3460 








3530 


2960 








3920 


4380 








4020 


4060 








4700 


3390 








4100 


3390 








4240 


3210 














3850 


3320 














4560 


3460 














5830 


3600 














5790 


2720 














3106 


3000 














3030 






































Av. 3 


530 


4393 


4103 


4031 


4027 


4041 


3826 


4350 



49 

gregates as finally placed in the pavement, for the same jobs and con- 
ditions as shown in Figure 19. In connection with each set of test 
specimens the cement was washed from a sample of concrete from the 
same batch and a sieve analysis was made upon the aggregate. In 
figure 20, the maximum and minimum percentages passing the No. 4 
sieve (opening .185 inches) is shown for each project. The shaded area 
stops at the percentage passing No. 4 sieve, upon which the proportions 
for the job were based, thus showing the relation between the maximum, 
minimum, and the proportioning base. 



TABLE XV 



Continued 





8 


9 




10 


11 


12 


13 




Sand and Gravel 

1:2:3.5, Stock 

Pile Road Mix 


Sand and Gravel 
1:2:3.5, Stock 
Pile Road Mix 


Sand and 
Gravel 
Hauled 

from pit, 

Central 

Mix 


Sand and 

Gravel 
Stock Pile 
Road Mix 


Sand and 

Gravel 

Piled on 

Sub-grade 

Road Mix 


3 and and Gravel 
Piled on Sub- 
grade, Road Mix 


4S10 


4560 


44S0 


4420 


4590 


5690 


3890 


5690 3750 


4590 


4310 


4480 


5300 


4590 


4840 


4030 


4450 3950 


4030 


4200 


4590 


5090 


3850 


4810 


3210 


4240 3350 


3990 


4450 


3780 


4760 


3600 


3640 


3570 


4660 4910 


4380 


4030 


4450 


4840 


3430 


3950 


2830 


4380 4210 


4630 


5303 


5360 


4130 


3430 


5260 


3320 


4910 3850 


4430 


4410 


5010 


3960 


4770 


3180 


3500 


3210 




4620 


5190 


5370 


5120 


4030 


3500 


3850 


3600 




4490 


5010 


3820 


4560 


4340 


3990 


3740 


4380 




4090 


3920 


3950 


4270 


4100 


3420 


4730 


3110 




3990 


4210 


4160 


4760 


4660 


4450 


3780 


4450 




4560 


4130 


4030 


4560 


4160 


3435 


2930 


4840 




3990 


4270 
5370 
5340 
5720 
5300 
3350 
4560 
4270 
4760 
3390 


4690 

4590 

4200 

4S10 

4660 

5220 

4840 

4340 

3990 - 

3530 

3430 

3740 

4730 

5120 

4910 

5680 

5580 

4340 

5010 

4270 

4490 

4210 

3530 


5060 
4910 
4770 
4130 
4980 
4030 
5190 




4520 
2690 
3180 
3290 
2580 
2890 
3350 
3000 
3180 
3560 
3390 
3710 
4030 
3390 
3710 
2400 
2220 
3780 
2860 


2015 
3890 
3000 


4520 
4340 
3920 
2899 
3490 
3350 
4420 
3640 
3250 
4060 
4060 
4340 
4700 
4520 
4620 
3810 
4?00 
4340 
4130 
4910 
4590 
3990 
3890 




5260 




5120 




4420 




3890 






4450 






4840 






3560 






4140 








4060 








4480 








4870 








5500 








5330 








5330 








5190 








5470 








5830 








5230 








4620 








5300 










4310 




| 




4630 








4490 




4420 










3640 

















Av. 



4603 



4540 



4130 



3610 



3590 



4145 



50 



It will be noted that the range in composition of the aggregates actu- 
ally in the concrete, it not any greater for the pit-ran material than 
for mixtures made from screened aggregates. The evidence from the 
tests reported herein, eonfirins the conclusion that pit-run gravel when 
properly handled will yield concrete of as uniform quality as may be 
ordinarily expected. 



A0& 3 Aforyf/Tts 



Sfr&ngtt? Tesf» F/a/cJ Spec/mans 

One Cocvrse Corronsfe / = trv&m&nt /ovuo rf/ghtvoy Comm/ooion 

Mox/murr> - AUn/rm/m Aver-oge 

1 Agg & Morrtns 





fioaa 


S \ 


7 
J? 

5 


// 13 

9 


X 

\ 




4- 
3 















O 










I 


















/2 


























_ 








* 
















i 
















8 


<mnn 






























1 




















svoo 









FIG. 19 — DIAGRAM SHOWING THE AVERAGE, MINIMUM AND MAXIMUM 

CRUSHING STRENGTHS OF SPECIMENS TAKEN IN THE FIELD DAILY 

ON 13 PROJECTS. Data taken from table numbers XD7 and XV. Numbers 

correspond to numbers in tables XIV and XV. 

VI. APPLICATION OF THEORY 

Use of Pit-Run Gravel and Mixtures Containing Various 
Amounts o£ Sand, It has been demonstrated in preceding chapters 
that satisfactory concrete can be made from mixtures of aggregates 
in which the amount of sand ranges from 33 to 100 percent. The only 
difference between the use of pit-run gravel and screened gravel is the 
fact that the cement ratio in the case of pit-run must be changed as 
often as necessary to correct the variations in the material. Outside of 
the grading, pit-run gravel should be in all respects of as high quality 
as screened materials. Whether screened or unscreened material should 
be used is entirely a matter of available material and relative economy. 

The method of use described in this bulletin is extremely simple of 
application in the field, and simplicity, in such a case makes for relia- 
bility. One test only is required. That is for the percentage of sand 
in the gravel. If it is not practicable to weigh the gravel when used, 
a test for weight per cubic foot will also be needed. In this case the 
procedure is: 

1. The percentage of sand is determined as follows : 

Apparatus. A small No. 4 sieve, and a scale or balance reading ac- 
curately to 1 oz. are required. A regular testing sieve is preferred, but 



51 

for rough work a piece of No. 4 commercial wire cloth may be lacked 
on the under side of a small bottomless box. 

Method. A sample containing 10 to 20 lbs. is placed on the No. 4 
screen and shaken until the material ceases to pass the sieve. The 



GO 



75 



70 



05 



QC 



S5-I 



50 



45 



*>■ I >*■ 



/ 



/ 



P/tPun 



Screens fiZ&ZJ 



1:3.75 



/:<* 



/■■4.25 



/■■35 



/••&#& 25 



1-2-35 



/:?5:/ 



/■2:35 



/: 3-3.5 



/■Z-3.5 



/:Z-3.5 



/'Z-3.5 



/■f:35 



/■■e:35 






// 



25 



2/ 



45 



34 



30 



20 



53 



00 



00 



27 



23 



Z3 



Ak Grosh/ng Lood 
Lbs, per Sq //? 



3 Months Months 



'Mo> 



3070 



3690 



3QIO 



35/0 



3766 



30<SO 



3(300 



30 70 



3390 



34GO 



3530 



4393 



4/03 



403J 



4027 



404/ 



3636 



4350 



46C3 



4540 



4/30 



30IO 



3390 



35 



3D 



4b. 



1 I I 



Z5 



1^2- 



20 



15 



FIG. 20 — DIAGRAM SHOWING RANGE IN SIEVE ANALYSIS AS DETER- 
MINED ON THE NUMBER FOUR SIEVE, FOR THE JOBS IN TABLES XIV 
AND XV. Maximum and minimum values as observer! are shown. Top of 
shaded portion indicates percentage passing number four sieve upon which 
proportions were based. Samples were taken from pavement while fresh and 
cement removed by washing thru a number 100 sieve. 



52 

material which passes the sieve is weighed. This weight is divided by 
the original weight of the entire sample, and the quotient, multiplied by 
100, is the percentage of sand in the pit-run gravel to use in connection 
with the diagrams in figure 15. 

2. From figure 15 the proportion to use for the class of concrete de- 
sired is selected. 

3. If it is necessary to measure the gravel by volume the above weight 
relation is converted to volumetric as follows : 

Weight per Cubic Foot, — Apparatus. A straight sided measure, 
of which the capacity can be accurately determined, to hold not less than 
one-half cubic foot and some method of weighing to the nearest pound 
are required. A 100 pound spring balance is convenient and easy to 
carry. 

Method. Since materials are measured on the work loose, as shoveled 
into wheelbarrows or other receptacles, the determination of weight 
should be made upon material in approximately the same condition. 
In order to secure comparable results, it is necessary that the procedure 
be followed exactly. 

In placing the material in the measure the shovel is held so that the 
end rests upon the top of the measure, and the material is allowed to 
slide off into the measure. When the measure is full, it is struck off level 
with the straight edge, weighed and the weight of the container sub- 
tracted. The remainder is divided by the inside volume of the measure in 
cubic feet, and the resulting figure is the loose weight per cubic foot of 
aggregate. The handling of the measure after striking off will cause a 
shrinkage due to the compacting of the material. No material should 
be added to fill up the measure. It is the weight of the loose volume that 
is wanted. Weight per cubic foot does not mean anything, unless the 
degree of compactness is defined. This is accomplished in this test by 
specifying the exact method of filling the measure. 

Assuming that a cubic foot of cement weighs 94 lbs. then weight pro- 
portion = 1 to a 

= 94 to 94 a divide each by the weight per cubic foot then vol- 
umetric proportion 

= 94 94 

94 wt. per cu. ft. of gravel 

94 
wt. per cu. ft. of gravel. 

When possible to do so it is good practice to get the weight per cubic 
foot by weighing a volume of the material as actually measured on the 
job. 

Methods of Using Pit-Run Gravel. Pit-run gravel may be used in 
each of three different cases : 

1. Enough cement may be used to make concrete of the desired class 
from the gravel without change. 



53 

2. The gravel may be separated into sand and coarse aggregate by 
screening:, and remixing in pre-determined proportions. 

3. The gravel may be made the equivalent of the proportion in case 
L } by adding coarse aggregate or sand, as may be required. 

Determining Costs. To make a comparative estimate of the costs 
of the three methods, the following information will be required : 

(a) Unit prices of cement, pit-run gravel, screened gravel and crushed 
stone, and cost of screening. 

(b) Quantities of materials required for one cubic yard of concrete, 
(e) Percentage of sand in the gravel, by weight, and the relative 

volumes of sand and gravel a unit volume of the pit-run will yield, 
and the weight per cubic foot of the pit-run. 

Item " a " will depend upon local conditions ; ' ' b " may be estimated 
as shown in the Iowa Highway Commission table of proportions (See 
Table XVI) and "c" must be determined by test, If a unite volume 
of pit-run gravel be separated into two sizes it will be found that the 
sum of the volumes of the two sizes will be more than the original 
volume. For instance, 1 cu. yd. of pit-run gravel may yield .70 cu. 
yd. of sand and .50 cu. yd. of coarse aggregate. The percentage of sand 
to use with the diagram for proportioning pit-run materials under case 
1 may be found as follows : 

70 =58.3 



Percentage of sand 



.70 + .50 



This figure will agree reasonably close with the percentage determined 
by separating the sizes by weighing. Therefore, the diagrams will apply 

TABLE XVI. IOWA HIGHWAY COMMISSION 
TABLE OF PROPORTIONS FOR SCREENED AND UNSCREENED GRAVEL 

AGGREGATE 





Proportion by weight 




Percent sand in ag- 
gregate by weight 


Pit run gravel lb. 

cement to lb 

gravel 


Screened gravel 

lb. cement to lb. 

sand to lb. 

screened gravel 


Approximate bbl. 
cement per cu yd. 


33 | 


1:5.18 
1:4.84 
1:4.59 
1:4.34 
1:4.10 
1:3.84 
1:3.60 
1:3.35 
1:3.10 
1:2.86 
1:2.61 
1:2.36 
1:2.12 
1:1.87 


1:1.71:3.47 
1:1.93:2.91 
1:2.06:2.53 
1:2.17:2.17 
1:2.25:1.85 
1:2.30:1.54 
1:2.34:1.26 
1:2.34:1.01 
1:2.33:0.77 
1:2.29:0.57 
1:2.22:0.39 
1:2.12:0.24 
1:2.01:0.11 
1:1.87 


1. 6 


34 to 40 j 

41 to 45 | 

46 to 50 | 

51 to 55 j 


1.67 
1. 74 

1.80 
1.87 


56 to 60 | 

61 to 65 | 

66 to 70 j 

71 to 75 | 

76 to 80 | 

81 to 85 | 

86 to 90 

91 to 95 | 


1.95 
2.04 
2.15 
2.26 
2.39 
2.53 
2. 71 
2.89 


96 to 100 


3. 13 







54 

to either volumetric or weight determinations of the percentage of sand. 
Having the above information the procedure is as follows : 

(1) The proportion for cement to gravel for case 1 is derived from 
the diagram Pig. 14. 

(2) The proportion of cement to sand to coarse aggregate which would 
be the equivalent to the mixture of case 1 is assumed. (For Class 1 
concrete use 1:2:4; Class 2, use 1 :2i/ 2 :5 ; Class 3, use 1 :3 :6.) 

(3) The comparative costs are computed: 

Example. Cement $2.00 per bbl. 

Pit-run gravel 1.00 per yd. 

Stone 2.00 per yd. 

Screening 50 per yd. 

Percentage of sand in gravel, 58.0 

Yield of sand .70 of volume of pit-run 

Yield of coarse aggregate 50 of volume of pit-run 

Case 1. Using Pit-Run Straight, Proportion 1 :4.0. 

Material required for 1 yd. of concrete 

Cement 1.68 bbl. 

Pit-run 1.00 yd. 

1.68 bbl. at $2.00 $3.36 

1 yd. pit-run at $1.00 1.00 

Material cost $4.36 

Case 2. Screening, and Remixing, Proportions 1:2:4. 

Material required : 

Cement 1.5 bbl. 

Sand 44 cu. yd. 

Pebbles 88 cu. yd. 

Yield of sand and pebbles from pit-run same as before. 

To produce .88 yd. of) pebbles it will be necessary to buy and screen 

88 

'^rpr cu. vd. of pit-run = 1.76 cu. vd. The cost of material is therefore : 

.o0 * 

1.5 bbl. cement, at $2.00 - $3.00 

1.76 yd. pit-run, at $1.00 1.76 

1.76 yd. screening, at $0.50 88 

$5.64 
Case 3, Adding Coarse Material, Proportion 1:2:4. 

Material required : 

Cement 1.5 bbl. 

Sand '. 44 cu. yd. 

Pebbles 88 cu. yd. 



55 

One yard of this gravel will yield about .70 cu. yd. of sand. There- 

.44 
fore to produce .44 cu. yd. sand— -n=.63 cu. yd. of pit-run will be re- 
quired. .63 3'd. pit-run will yield .44 yd. sand and .31 yd. stone, leaving 
.88 — .31 = .57 yd. stone to bet added. 

Cement 1.55 bbl., at $2.00 $3.00 

Pit-run .63 yd., at $1.00 63 

Stone, .57 yd., at $2.00 1.14 



$4.77 



The same method of analysis will apply in estimating the relative 
economy of using different mixtures of sand and coarse aggregate. 



























































r 














i: 














V 














K 







































































Sieve Number 

FIG. 21 — SIEVE ANALYSIS DIAGRAM SHOWING RANGE IN SIEVE AN- 
ALYSIS OF PIT RUN GRAVEL USED ON PRIMARY ROAD PAVING IN 
PALO ALTO COUNTY IN 1920. 

Handling Pit-Run Gravel. In using pit-run gravel, such a system 
should be used, that individual loads will not be kept distinct but will 
be distributed through a pile of the material, and in general the larger 
the pile the better. In paving work pit-run gravel should not be strung 
along the road in small piles. The variation is likely to be so large in 
such a case that control of proportions will be extremely difficult. The 
following example from practice illustrates the beneficial effect of using 
pit-run gravel from a stock pile. 

The pit-run gravel used on an Iowa primary road paving project in 
Palo Alto County was excavated by means of a slack line cableway, and 



56 

piled on the bank. It was then loaded upon industrial railway cars 
by means of a Barber-Greene loader, and hauled some two miles to the 
project. The following Table XVII from the report of the preliminary 
investigation of the deposit gives the physical characteristics of the 
gravel in place. This material is typical of the gravels covered by this 
bulletin. 

From these tests it will be noted that the percentage of sand in the 
aggregate ranged from minimum of 53.2 to a maximum of 85.8 the 
mean value being 68.85. 

During the process of construction, samples of the concrete were taken 
from the pavement every day, the cement removed by washing and a 
sieve analysis run upon the gravel. Figure 21 shows the range in com- 
parison of the gravel as actually incorporated in the concrete during 
24 days work in which time 1.86 miles of pavement were completed. 
It will be noted that the range in the percentage of sand) was from a 
minimum of 66.8 to a maximum of 75.9, the mean value being 70.77. 



TABLE XVII. IOWA STATE HIGHWAY COMMISSION, DEPAETMENT OF 
MATEEIALS AND TESTS. EEPOET OF GEAVEL PIT INVESTIGATION 

County, Palo Alto; Township, Emmet sburg; Location, Sw Se Sec. 35; Date of In- 
vestigation: from January, 1920; Contemplated for Use on Paving; Average 
Haul, iy 2 End Miles; Distance to E. B,, 2 Miles; to Electic Power, 2 Miles; 

To Eiver, On It. 







ft 








-^ 





0" 


Pebbles Ret. on 


No. 8 Sieve 




ft 

<v 

ft^ 
03 


is 4-> 

-fa 
a to 

fl'fl 


CD +J 

o> 


a; w 

as 


a; 
<x> 

m > 

HO 




a 


5® 


w 










o 

M 

HZ 


ffi § 


&5 


S 
0® 


0> 


El 


4.0 


4.0 


10.6 


2" 




1.13 


OK 


72.6 


82.7 


14.0 


3.3 


0.0 


2 


4.0 


4.0 


11.7 


2" 




1.2 


OK 


60.6 


77.5 


12.0 


7.3 


3.2 


3 


4.0 


4.0 


12.1 


2" 




1.2 


OK 


61.6 


71.8 


22.2 


5.1 


0.9 


4 


4.1 


4.1 


12.6 


2" 




1.2 


OK 


61.2 


47.1 


50.7 


1.3 


0.9 


5 


2.9 


2.9 


10.8 


2" 




1.5 


OK 


68.8 


81.9 


4.8 


9.2 


4.1 


6 


On bar 


4.8 


iy 2 " 




0.4 


OK 


56.0 


78 5 


20.1 


1.4 


0.0 


7 


On bar 


4.6 


i" 




2.0 


OK 


67.4 


64.5 


28.4 


7.1 


0.0 


8 


On bar 


5.0 


%" 




2.0 


OK 


68.7 


75.5 


23.9 


0.6 


0.0 


Al 


3.0 


3.0 


10.3 


1%" 




4.8 


OK 


68.0 


83.8 


7.3 


8.9 


0.0 


2 


2.5 


3.5 


10.7 


1%" 




3.2 


OK 


76.4 


90.1 


5.0 


4.9 


0.0 


3 


3.5 


3.5 


11.6 


2" 




2.7 


OK 


64.7 


87.9 


8.4 


3.7 


0.0 


Bl 


3.0 


4.0 


9.0 


iy 2 " 




4.4 


OK 


54.3 


79.1 


17.6 


2.7 


0.6 


2 


4.0 


5.0 


8.6 


i" 




4.5 


OK 


72.1 


67.3 


28.8 


3.9 


0.0 


3 


4.0 


5.0 


8.8 


%" 




4.1 


OK 


80.6 


76.6 


19.6 


3.8 


0.0 


CI 


4.0 


4.5 


8.6 


1%" 




2.7 


OK 


53.2 


67.7 


29.4 


2.9 


0.0 


2 


4.0 


5.0 


9.0 


ii/>" 




2.9 


OK 


65.4 


79.3 


14.8 


5.9 


0.0 


3 


4.2 


5.2 


8.7 


¥>" 




3.5 


OK 


78.5 


83.9 


8.1 


8.0 


0.0 


A2 


Underwater 


33.0 


6" 


1 


0.64 


OK 


81.1 


79.8 


19.5 


0.3 


0.4 


B2 


Underwater 


33.0 


6" 


1 


0.4 


OK 


80.1 


76.9 


20.3 


0.4 


2.4 


C2 


Underwater 


33.0 


6" 


1 


0.9 


OK 


85.8 


85.8 


12.1 


1.5 


0.6 



Note : C4, C5 and C6 Gumbo and Clay 8' deep. 



P. J. Preston, Chief of Party. 



BULLETINS OF THE ENGINEERING EXPERIMENT STATION 

l The Iowa State College Sewage Disposal Plant Investigations. 
Bacteriological Investigations of the Iowa State College Sewage. 
•No. 3. Data of Iowa Sewage and Sewage Disposal. 

I, Bacteriological Investigations of the Iowa State College Sewage Disposal Plant. 
The Chemical Composition of the Sewage of the Iowa State College Sewage Disposal 

Plant. 
*No. 6. Tests of Iowa Common Brick. 
*No. 7. Sewage Disposal in Iowa. 
•No. 8. Tests of Dry Press Brick Used in Iowa. 

9. Notes on Steam Generation with Iowa Coal. 
•No. 10. Dredging by the Hydraulic Method. 
•No. 11. An Investigation of Some Iowa Sewage Disposal Systems. 

II, No. 6. The Good Roads Problem in Iowa. 
•Vol. Ill, No. 1. Tests of Cement. 

III, No. 2. State Railroad Taxation. 

*Vol. III. No. S. Steam Generation with Iowa Coals. 
Ill, No. 4. Incandescent Lamp Testing. 
III. No. 5. Steam Pipe Covering Tests. 
IT, No. 6. The Assessment of Drainage Districts. 
*Vol. IV. No. 1. Tests of Iowa Limes. 

TV, No. 2. Holding Power of Nails in Single Shear. 
.", No. 3. Miracle Contest Papers for 1908. (Theses on Cement and Concrete.) 
*Vo! IV. No. 4. Miracle Prize Papers for 1909. (Theses on Cement and Concrete.) 
•Vol. IV, No. 5. Sanitary Examination of Water Supplies. 
Vol. IV. No. 6. Sewage Disposal Plants for Private Houses. 
No. 25. Electric Power on the Farm. 

No. 26. The Production of Excessive Hydrogen Sulfid in Sewage Disposal Plants and Con- 
sequent Disintegration of the Concrete. 
No. 27. A Study of Iowa Population as Related to Industrial Conditions. 
23. History of Road Legislation in Iowa. 
29. Cost of Producing Power with Iowa Coals. 
No. 30. The Determination of Internal Temperature Range in Concrete Arch Bridges. 
*No. 31. The Theory of Loads on Pipes in Ditches, and Tests of Cement and Clay Drain 
Tile and Sewer Pipe. 
No. 32. A Topographical Survey of the Spirit and Okoboji Lakes Region. 
No. 33. House Heating Fuel Tests. 

34. The Use of Iowa Gravel for Concrete. 
No. 35. The Iowa Engineering Experiment Station and its Service to the Industries of the 

State. 
No. 36. Report of the Investigations on Drain Tile of Committee C-6, American Society for 

Testing Materials. 
No. 37. Illuminating Power of Kerosenes. 
No. 38. Electric Central Station Operation In Iowa. 
No. 39. Good Roads and Community Life. 
*No. 40. An Investigation of Iowa Fire Clays. 

41. Sewage Disposal for Village and Rural Homes. 
No. 42. A Study of Oil Engines in Iowa Power Plants. 
No. 43. Practical Handling of Iowa Clays. 
No. 44. Locomotive Tests with Iowa and Illinois Coals. 
No. 45. Investigations of Gravel for Road Surfacing. 

No. 46. Electric Pumping, with Results of Tests and Operating Records. 
No. 47. The Supporting Strength of Sewer Pipe in Ditches, and Methods of Testing Sewer 

Pipe in Laboratories to Determine their Ordinary Supporting Strength. 
No. 48. The Early Purchase and Storage of Iowa Coal. 
No. 49. An Investigation of Tests of Iowa Shale Drain Tile. 
The Theory of Underdrainage. 
"1. Recommendations for Farm Drainage. 

52. The Spacing and Depths of Laterals in Iowa Underdrainage Systems and the Rate 

of Runoff from Them. 

53. Load Concentrations on Steel Floor-Joists of Wood-Floor Highway Bridges. 
No. 54. An Investigation of the Protective Values of Structural Steel Paints. 

55. Lighting for Country Homes and Village Communities. 
"6. Traffic on Iowa Highways. 

supporting Strength of Drain Tile and Sewer Pipe Under Different Pipe-Laying 
Conditions. 
58. Possibilities of Pottery Manufacture from Iowa Clays. 
No. 59. Effects on Concrete of Immersion in Boiling Water and Oven Drying. 

"i. Method of Proportioning Concrete Materials — Screened and Unscreened Gravel. 

*Out of print. 

Bulletins not out of print many be obtained free of charge upon request addressed to The 
Director, Engineering Experiment Station, Sta. A, Ames, Iowa. 



LIBRARY OF CONGRESS 



019 454 338 4 



The College 

The Iowa State College of Agriculture and 
Mechanic Arts conducts work along five major lines : 

Agriculture 
Engineering 
Home Economics 
Industrial Science 
Veterinary Medicine 

The Graduate College conducts advanced research 
and instruction in all these lines. 

Four-year, five-year, and six-year collegiate courses 
are offered in different divisions of the College. Non- 
collegiate courses are offered in agriculture, trades 
and industries and home economics. Summer Sessions 
include graduate, collegiate, and non-collegiate work. 
Short courses are offered in the winter. 

Extension courses are conducted at various points 
throughout the state. 

Research work is conducted in the Agricultural and 
Engineering Experiment Stations and in the Veteri- 
nary Research Laboratory. 

Special announcements of the different branches of 
the work are supplied, free of charge, on application. 
The general bulletins will be sent on request. 

Address The Registrar, 

Iowa State College, 
Ames, Iowa. 



